diff --git a/pytriqs/gf/local/imfreq.pxd b/pytriqs/gf/local/imfreq.pxd
index caad25c2..33163e29 100644
--- a/pytriqs/gf/local/imfreq.pxd
+++ b/pytriqs/gf/local/imfreq.pxd
@@ -5,8 +5,7 @@ cdef extern from "triqs/gfs/imfreq.hpp" namespace "triqs::gfs" :
         statistic_enum statistic
         imfreq_domain ()
 
-    #cdef cppclass mesh_imfreq "triqs::gfs::linear_mesh<triqs::gfs::imfreq::domain_t>"  :
-    cdef cppclass mesh_imfreq "triqs::gfs::linear_mesh<triqs::gfs::matsubara_domain<true>>"  :
+    cdef cppclass mesh_imfreq "triqs::gfs::mesh<triqs::gfs::imfreq>"  :
         mesh_imfreq ()
         mesh_imfreq (mesh_imfreq &)
         imfreq_domain & domain()
@@ -14,7 +13,7 @@ cdef extern from "triqs/gfs/imfreq.hpp" namespace "triqs::gfs" :
         long size()
         bint operator ==( mesh_imfreq &)
 
-    cdef mesh_imfreq make_mesh_imfreq "triqs::gfs::make_gf_mesh<triqs::gfs::imfreq>" (double beta, statistic_enum S, size_t n_max)
+    cdef mesh_imfreq make_mesh_imfreq "triqs::gfs::mesh<triqs::gfs::imfreq>" (double beta, statistic_enum S, size_t n_max)
     #cdef mesh_imfreq make_mesh_imfreq "triqs::gfs::gf_implementation::gf_factories<triqs::gfs::imfreq,triqs::gfs::matrix>::make_mesh" (double beta, statistic_enum S, size_t n_max)
     
     cdef cppclass gf_imfreq "triqs::python_tools::cython_proxy<triqs::gfs::gf_view<triqs::gfs::imfreq> >" :
diff --git a/pytriqs/gf/local/imtime.pxd b/pytriqs/gf/local/imtime.pxd
index c77ce2e4..cca2c168 100644
--- a/pytriqs/gf/local/imtime.pxd
+++ b/pytriqs/gf/local/imtime.pxd
@@ -5,8 +5,7 @@ cdef extern from "triqs/gfs/imtime.hpp" namespace "triqs::gfs" :
         statistic_enum statistic
         imtime_domain ()
 
-    #cdef cppclass mesh_imtime "triqs::gfs::linear_mesh<triqs::gfs::imtime::domain_t>"  :
-    cdef cppclass mesh_imtime "triqs::gfs::linear_mesh<triqs::gfs::matsubara_domain<false>>" :
+    cdef cppclass mesh_imtime "triqs::gfs::mesh<triqs::gfs::imtime>"  :
         mesh_imtime ()
         mesh_imtime (mesh_imtime &)
         imtime_domain & domain()
@@ -15,7 +14,7 @@ cdef extern from "triqs/gfs/imtime.hpp" namespace "triqs::gfs" :
         long kind()
         bint operator ==( mesh_imtime &)
 
-    cdef mesh_imtime make_mesh_imtime "triqs::gfs::make_gf_mesh<triqs::gfs::imtime>" (double beta, statistic_enum S, size_t n_time_slices, mesh_enum mk)
+    cdef mesh_imtime make_mesh_imtime "triqs::gfs::mesh<triqs::gfs::imtime>" (double beta, statistic_enum S, size_t n_time_slices, mesh_enum mk)
     #cdef mesh_imtime make_mesh_imtime "triqs::gfs::gf_factories<triqs::gfs::imtime>::make_mesh" (double beta, statistic_enum S, size_t n_time_slices, mesh_enum mk)
 
     cdef cppclass gf_imtime "triqs::python_tools::cython_proxy<triqs::gfs::gf_view<triqs::gfs::imtime>>" :
diff --git a/pytriqs/gf/local/legendre.pxd b/pytriqs/gf/local/legendre.pxd
index ec457d98..ca5307fc 100644
--- a/pytriqs/gf/local/legendre.pxd
+++ b/pytriqs/gf/local/legendre.pxd
@@ -6,15 +6,14 @@ cdef extern from "triqs/gfs/legendre.hpp" namespace "triqs::gfs" :
         statistic_enum statistic
         legendre_domain ()
 
-    #cdef cppclass mesh_legendre "triqs::gfs::discrete_mesh<triqs::gfs::legendre::domain_t>":
-    cdef cppclass mesh_legendre "triqs::gfs::discrete_mesh<triqs::gfs::legendre_domain>":
+    cdef cppclass mesh_legendre "triqs::gfs::mesh<triqs::gfs::legendre>"  :
         mesh_legendre ()
         mesh_legendre (mesh_legendre &)
         legendre_domain & domain()
         long size()
         bint operator == (mesh_legendre &)
 
-    cdef mesh_legendre make_mesh_legendre "triqs::gfs::make_gf_mesh<triqs::gfs::legendre>" (double beta, statistic_enum S, size_t n_leg)
+    cdef mesh_legendre make_mesh_legendre "triqs::gfs::mesh<triqs::gfs::legendre>" (double beta, statistic_enum S, size_t n_leg)
     #cdef mesh_legendre make_mesh_legendre "triqs::gfs::gf_factories<triqs::gfs::legendre>::make_mesh" (double beta, statistic_enum S, size_t n_leg)
 
     cdef cppclass gf_legendre "triqs::python_tools::cython_proxy<triqs::gfs::gf_view<triqs::gfs::legendre>>" :
diff --git a/pytriqs/gf/local/refreq.pxd b/pytriqs/gf/local/refreq.pxd
index d73c0e36..2c9bfc74 100644
--- a/pytriqs/gf/local/refreq.pxd
+++ b/pytriqs/gf/local/refreq.pxd
@@ -3,8 +3,7 @@ cdef extern from "triqs/gfs/refreq.hpp" namespace "triqs::gfs" :
     cdef cppclass refreq_domain :
         refreq_domain()
 
-    #cdef cppclass mesh_refreq "triqs::gfs::linear_mesh<triqs::gfs::refreq::domain_t>"  :
-    cdef cppclass mesh_refreq "triqs::gfs::linear_mesh<triqs::gfs::R_domain>"  :
+    cdef cppclass mesh_refreq "triqs::gfs::mesh<triqs::gfs::refreq>"  :
         mesh_refreq ()
         mesh_refreq (mesh_refreq &)
         refreq_domain & domain()
@@ -14,7 +13,7 @@ cdef extern from "triqs/gfs/refreq.hpp" namespace "triqs::gfs" :
         double kind()
         bint operator ==( mesh_refreq &)
 
-    cdef mesh_refreq make_mesh_refreq "triqs::gfs::make_gf_mesh<triqs::gfs::refreq>" (double omega_min, double omega_max, size_t n_freq, mesh_enum mk)
+    cdef mesh_refreq make_mesh_refreq "triqs::gfs::mesh<triqs::gfs::refreq>" (double omega_min, double omega_max, size_t n_freq, mesh_enum mk)
     #cdef mesh_refreq make_mesh_refreq "triqs::gfs::gf_factories<triqs::gfs::refreq>::make_mesh" (double omega_min, double omega_max, size_t n_freq, mesh_enum mk)
 
     cdef cppclass gf_refreq "triqs::python_tools::cython_proxy<triqs::gfs::gf_view<triqs::gfs::refreq>>" :
diff --git a/pytriqs/gf/local/retime.pxd b/pytriqs/gf/local/retime.pxd
index 09efe701..797c12b8 100644
--- a/pytriqs/gf/local/retime.pxd
+++ b/pytriqs/gf/local/retime.pxd
@@ -3,8 +3,7 @@ cdef extern from "triqs/gfs/retime.hpp" namespace "triqs::gfs" :
     cdef cppclass retime_domain :
         retime_domain()
 
-    #cdef cppclass mesh_retime "triqs::gfs::linear_mesh<triqs::gfs::retime::domain_t>"  :
-    cdef cppclass mesh_retime "triqs::gfs::linear_mesh<triqs::gfs::R_domain>"  :
+    cdef cppclass mesh_retime "triqs::gfs::mesh<triqs::gfs::retime>"  :
         mesh_retime ()
         mesh_retime (mesh_retime &)
         retime_domain & domain()
@@ -14,7 +13,7 @@ cdef extern from "triqs/gfs/retime.hpp" namespace "triqs::gfs" :
         double kind()
         bint operator ==( mesh_retime &)
 
-    cdef mesh_retime make_mesh_retime  "triqs::gfs::make_gf_mesh<triqs::gfs::retime>" (double t_min, double t_max, size_t n_freq, mesh_enum mk)
+    cdef mesh_retime make_mesh_retime  "triqs::gfs::mesh<triqs::gfs::retime>" (double t_min, double t_max, size_t n_freq, mesh_enum mk)
     #cdef mesh_retime make_mesh_retime "triqs::gfs::gf_factories<triqs::gfs::retime>::make_mesh" (double t_min, double t_max, size_t n_freq, mesh_enum mk)
 
     cdef cppclass gf_retime "triqs::python_tools::cython_proxy<triqs::gfs::gf_view<triqs::gfs::retime>>" :
diff --git a/pytriqs/gf/local/two_real_times.pxd b/pytriqs/gf/local/two_real_times.pxd
index a4ddc70e..61c8f795 100644
--- a/pytriqs/gf/local/two_real_times.pxd
+++ b/pytriqs/gf/local/two_real_times.pxd
@@ -3,8 +3,7 @@ cdef extern from "triqs/gfs/two_real_times.hpp" namespace "triqs::gfs" :
     cdef cppclass two_real_times_domain :
         two_real_times_domain()
 
-    #cdef cppclass mesh_retime "triqs::gfs::linear_mesh<triqs::gfs::retime::domain_t>"  :
-    cdef cppclass mesh_two_real_times "triqs::gfs::mesh_product<triqs::gfs::linear_mesh<triqs::gfs::R_domain>,triqs::gfs::linear_mesh<triqs::gfs::R_domain>>"  :
+    cdef cppclass mesh_two_real_times "triqs::gfs::mesh<triqs::gfs::two_real_times>"  :
         mesh_two_real_times ()
         mesh_two_real_times (mesh_two_real_times &)
         two_real_times_domain & domain()
@@ -14,7 +13,7 @@ cdef extern from "triqs/gfs/two_real_times.hpp" namespace "triqs::gfs" :
         double kind()
         bint operator ==( mesh_two_real_times &)
 
-    cdef mesh_two_real_times make_mesh_two_real_times  "triqs::gfs::make_gf_mesh<triqs::gfs::two_real_times>" (double t_max, double n_time_slices)
+    cdef mesh_two_real_times make_mesh_two_real_times  "triqs::gfs::mesh<triqs::gfs::two_real_times>" (double t_max, double n_time_slices)
 
     cdef mesh_retime & get_1d_mesh_from_2times_mesh "triqs::gfs::get_1d_mesh_from_2times_mesh" (mesh_two_real_times &)
 
diff --git a/test/triqs/gf/c++11/gf_re_im_freq_time.cpp b/test/triqs/gf/c++11/gf_re_im_freq_time.cpp
index d2601806..14f3fd78 100644
--- a/test/triqs/gf/c++11/gf_re_im_freq_time.cpp
+++ b/test/triqs/gf/c++11/gf_re_im_freq_time.cpp
@@ -34,11 +34,11 @@ try {
  auto G_w_tau= make_gf<refreq_imtime, scalar_valued>(wmin, wmax, n_re_freq, beta, Fermion, n_im_time);
  auto G_w= make_gf<refreq, scalar_valued>(wmin, wmax, n_re_freq);
 
- auto G_t_tau= make_gf<cartesian_product<retime,imtime>, scalar_valued>(  make_gf_mesh<retime>(tmin, tmax, n_re_time), make_gf_mesh<imtime>(beta, Fermion, n_im_time));
+ auto G_t_tau= make_gf<cartesian_product<retime,imtime>, scalar_valued>(mesh<retime>(tmin, tmax, n_re_time), mesh<imtime>(beta, Fermion, n_im_time));
  //auto G_t_tau_N= make_gf<cartesian_product<retime,imtime>, scalar_valued>(  {tmin, tmax, n_re_time}, {beta, Fermion, n_im_time});
 
- auto G_w_wn2 = make_gf<cartesian_product<refreq,imfreq>, scalar_valued>( make_gf_mesh<refreq>(wmin, wmax, n_re_freq), make_gf_mesh<imfreq>(beta, Fermion, n_im_freq));
- auto G_w_tau2 = make_gf<cartesian_product<refreq,imtime>, scalar_valued>( make_gf_mesh<refreq>(wmin, wmax, n_re_freq), make_gf_mesh<imtime>(beta, Fermion, n_im_time,full_bins));
+ auto G_w_wn2 = make_gf<cartesian_product<refreq,imfreq>, scalar_valued>( mesh<refreq>(wmin, wmax, n_re_freq), mesh<imfreq>(beta, Fermion, n_im_freq));
+ auto G_w_tau2 = make_gf<cartesian_product<refreq,imtime>, scalar_valued>( mesh<refreq>(wmin, wmax, n_re_freq), mesh<imtime>(beta, Fermion, n_im_time,full_bins));
 
 
  //auto g_tau = slice_mesh1(G_w_tau(),1);
diff --git a/triqs/gfs/block.hpp b/triqs/gfs/block.hpp
index c8c20d59..95766ad6 100644
--- a/triqs/gfs/block.hpp
+++ b/triqs/gfs/block.hpp
@@ -29,9 +29,13 @@ namespace triqs { namespace gfs {
 
  struct block_index {};
 
+ template<typename Opt> struct mesh<block_index,Opt> : discrete_mesh<discrete_domain> {
+  mesh() = default;
+  mesh(size_t s) : discrete_mesh<discrete_domain>(s) {}
+ };
+
  namespace gfs_implementation { 
 
-  template<typename Opt> struct mesh<block_index,Opt>                { typedef discrete_mesh<discrete_domain> type;};
   template<typename Target, typename Opt> struct h5_name<block_index,Target,Opt>      { static std::string invoke(){ return  "BlockGf";}};
 
   /// ---------------------------  h5_rw ---------------------------------
@@ -62,7 +66,7 @@ namespace triqs { namespace gfs {
 
   template<typename Target, typename Opt>
    struct factories<block_index,Target,Opt>  { 
-    typedef typename mesh<block_index, Opt>::type mesh_t;
+    typedef mesh<block_index, Opt> mesh_t;
     typedef gf<block_index,Target> gf_t;
     typedef gf_view<block_index,Target> gf_view_t;
 
@@ -76,11 +80,11 @@ namespace triqs { namespace gfs {
      return gf_t(mesh_t(block_names), std::move(V), nothing(), nothing() );
     }
 
-   /* static gf_t make_gf(std::initializer_list<Target> const & l) { 
-      auto v = std::vector<Target> {l};
-      return make_gf(v);
-    }
-*/
+    /* static gf_t make_gf(std::initializer_list<Target> const & l) { 
+       auto v = std::vector<Target> {l};
+       return make_gf(v);
+       }
+       */
     /* template<typename... Args>
        static gf_t make_gf(size_t N, Args&& ...args)  {
        std::vector<Target> V; V.reserve(N);
@@ -114,7 +118,7 @@ namespace triqs { namespace gfs {
      static gf_view_t make_gf_view(std::vector<GF> && V)      { return gf_view_t ( mesh_t(V.size()), std::move(V), nothing(), nothing() ) ; }
 
    };
- 
+
  } // gfs_implementation
 
  // -------------------------------   Free function   --------------------------------------------------
@@ -133,7 +137,7 @@ namespace triqs { namespace gfs {
 
  // also experimental
  // an iterator over the block
-  template<typename Target, typename Opt>
+ template<typename Target, typename Opt>
   class block_gf_iterator : 
    public boost::iterator_facade< block_gf_iterator<Target,Opt>, typename Target::view_type , boost::forward_traversal_tag, typename Target::view_type  > {
     friend class boost::iterator_core_access;
@@ -149,11 +153,11 @@ namespace triqs { namespace gfs {
     void increment() { ++mesh_it; }
     bool at_end() const { return mesh_it.at_end();}
    };
- 
-  template<typename Target, typename Opt, bool B>
+
+ template<typename Target, typename Opt, bool B>
   block_gf_iterator<Target,Opt> begin(gf_impl<block_index,Target,Opt,B> const & bgf) { return {bgf,false};}
-  
-  template<typename Target, typename Opt, bool B>
+
+ template<typename Target, typename Opt, bool B>
   block_gf_iterator<Target,Opt> end(gf_impl<block_index,Target,Opt,B> const & bgf) { return {bgf,true};}
 
 
diff --git a/triqs/gfs/curry.hpp b/triqs/gfs/curry.hpp
index 15864121..0fe1c9c9 100644
--- a/triqs/gfs/curry.hpp
+++ b/triqs/gfs/curry.hpp
@@ -119,7 +119,7 @@ namespace triqs { namespace gfs {
 	   Opt>
     curry (gf_impl<cartesian_product<Ms...>, Target,Opt,B> const & g) { 
     auto comp =  pv_<cartesian_product<Ms...>,pos...>::m(std::make_tuple(),g.mesh().components());
-    typedef typename mesh< typename pv_<cartesian_product<Ms...>,pos...>::type,Opt>::type m_t;
+    typedef mesh< typename pv_<cartesian_product<Ms...>,pos...>::type,Opt> m_t;
     return {triqs::tuple::apply_construct<m_t>(comp),curry_polymorphic_lambda<gf_view<cartesian_product<Ms...>, Target,Opt>, pos ...>{g}, nothing(), nothing()}; 
    };
 
diff --git a/triqs/gfs/gf.hpp b/triqs/gfs/gf.hpp
index 9c12af9a..27fcc0d5 100644
--- a/triqs/gfs/gf.hpp
+++ b/triqs/gfs/gf.hpp
@@ -34,13 +34,12 @@ namespace triqs { namespace gfs {
  using arrays::make_shape;
 
  // GENERALISE matrxi TO DEFAULT
+ template<typename Variable, typename Opt=void> struct mesh;
  template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf;         // the value class
  template<typename Variable, typename Target=matrix_valued, typename Opt=void> class gf_view;    // the view class
 
  // various implementation traits
  namespace gfs_implementation { // never use using of this... 
-  // what is the mesh
-  template<typename Variable, typename Opt> struct mesh;
 
   // evaluator regroup functions to evaluate the function. Cf descriptors
   template<typename Variable, typename Target, typename Opt> struct evaluator{ static constexpr int arity = 0;};
@@ -80,9 +79,6 @@ namespace triqs { namespace gfs {
  template <typename Variable, typename Target=matrix_valued, typename Opt=void, typename ... U> 
   gf_view<Variable,Target,Opt> make_gf_view(U && ... x) { return gfs_implementation::factories<Variable,Target,Opt>::make_gf_view(std::forward<U>(x)...);}
 
- template <typename Variable, typename Opt=void, typename ... U> 
-  typename gfs_implementation::mesh<Variable,Opt>::type make_gf_mesh(U && ... x) { return gfs_implementation::mesh<Variable,Opt>::make(std::forward<U>(x)...);}
-
  template<typename Variable, typename Target, typename Opt> struct gf_desc{};
  template<typename Descriptor> struct gf_tag{};
 
@@ -105,7 +101,7 @@ namespace triqs { namespace gfs {
     typedef Variable variable_t;
     typedef Opt option_t;
 
-    typedef typename gfs_implementation::mesh<Variable,Opt>::type                                mesh_t;
+    typedef mesh<Variable,Opt>                                                                  mesh_t;
     typedef typename mesh_t::domain_t                                                           domain_t;
     typedef typename mesh_t::mesh_point_t                                                       mesh_point_t;
     typedef typename mesh_t::index_t                                                            mesh_index_t;
diff --git a/triqs/gfs/imfreq.hpp b/triqs/gfs/imfreq.hpp
index bf5a9b3c..7f574483 100644
--- a/triqs/gfs/imfreq.hpp
+++ b/triqs/gfs/imfreq.hpp
@@ -29,23 +29,20 @@ namespace triqs { namespace gfs {
 
  struct imfreq {};
 
+ template<typename Opt> struct mesh<imfreq,Opt> : linear_mesh<matsubara_domain<true>> {
+  typedef  linear_mesh<matsubara_domain<true>> B;
+  static double m1(double beta) { return std::acos(-1)/beta;}
+  mesh() = default;
+  mesh (double beta, statistic_enum S, size_t Nmax = 1025) : 
+   B(typename B::domain_t(beta,S), S==Fermion?m1(beta):0, S==Fermion?(2*Nmax+1)*m1(beta): 2*Nmax*m1(beta), Nmax, without_last){}
+ };
+
  namespace gfs_implementation { 
 
-  // mesh type and its factories
-  template<typename Opt> struct mesh<imfreq,Opt>                { 
-   typedef linear_mesh<matsubara_domain<true>> type;
-   typedef typename type::domain_t domain_t;
-
-   static type make(double beta, statistic_enum S, size_t Nmax = 1025) {
-    double m1 = std::acos(-1)/beta;
-    return type( domain_t(beta,S), S==Fermion?m1:0, S==Fermion?(2*Nmax+1)*m1: 2*Nmax*m1, Nmax, without_last);
-   }
-  };
-
   //singularity
   template<typename Opt> struct singularity<imfreq,matrix_valued,Opt>  { typedef local::tail type;};
   template<typename Opt> struct singularity<imfreq,scalar_valued,Opt>  { typedef local::tail type;};
-  
+
   //h5 name
   template<typename Opt> struct h5_name<imfreq,matrix_valued,Opt>      { static std::string invoke(){ return "ImFreq";}};
 
@@ -68,44 +65,44 @@ namespace triqs { namespace gfs {
   template<typename Opt> struct data_proxy<imfreq,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
 
   // -------------------------------   Factories  --------------------------------------------------
-  
+
   // matrix_valued
   template<typename Opt> struct factories<imfreq,matrix_valued,Opt> { 
-    typedef gf<imfreq,matrix_valued,Opt> gf_t;
-    
-    template<typename MeshType>
+   typedef gf<imfreq,matrix_valued,Opt> gf_t;
+
+   template<typename MeshType>
     static gf_t make_gf(MeshType && m, tqa::mini_vector<size_t,2> shape, local::tail_view const & t) {
-      typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
-      return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-    }
-    static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape) {
-      return make_gf(mesh<imfreq,Opt>::make(beta,S), shape, local::tail(shape));
-    }
-    static gf_t make_gf(double beta, statistic_enum S,  tqa::mini_vector<size_t,2> shape, size_t Nmax) {
-      return make_gf(mesh<imfreq,Opt>::make(beta,S,Nmax), shape, local::tail(shape));
-    }
-    static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape, size_t Nmax, local::tail_view const & t) {
-      return make_gf(mesh<imfreq,Opt>::make(beta,S,Nmax), shape, t);
+     typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
+     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
     }
+   static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape) {
+    return make_gf(mesh<imfreq,Opt>(beta,S), shape, local::tail(shape));
+   }
+   static gf_t make_gf(double beta, statistic_enum S,  tqa::mini_vector<size_t,2> shape, size_t Nmax) {
+    return make_gf(mesh<imfreq,Opt>(beta,S,Nmax), shape, local::tail(shape));
+   }
+   static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape, size_t Nmax, local::tail_view const & t) {
+    return make_gf(mesh<imfreq,Opt>(beta,S,Nmax), shape, t);
+   }
   };
-  
+
   // scalar_valued
   template<typename Opt> struct factories<imfreq,scalar_valued,Opt> { 
    typedef gf<imfreq,scalar_valued,Opt> gf_t;
 
    template<typename MeshType>
-   static gf_t make_gf(MeshType && m, local::tail_view const & t) {
-    typename gf_t::data_regular_t A(m.size()); A() =0;
-    return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-   }
+    static gf_t make_gf(MeshType && m, local::tail_view const & t) {
+     typename gf_t::data_regular_t A(m.size()); A() =0;
+     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
+    }
    static gf_t make_gf(double beta, statistic_enum S) {
-     return make_gf(mesh<imfreq,Opt>::make(beta,S), local::tail(tqa::mini_vector<size_t,2> (1,1)));
+    return make_gf(mesh<imfreq,Opt>(beta,S), local::tail(tqa::mini_vector<size_t,2> (1,1)));
    }
    static gf_t make_gf(double beta, statistic_enum S, size_t Nmax) {
-    return make_gf(mesh<imfreq,Opt>::make(beta,S,Nmax), local::tail(tqa::mini_vector<size_t,2> (1,1)));
+    return make_gf(mesh<imfreq,Opt>(beta,S,Nmax), local::tail(tqa::mini_vector<size_t,2> (1,1)));
    }
    static gf_t make_gf(double beta, statistic_enum S, size_t Nmax, local::tail_view const & t) {
-    return make_gf(mesh<imfreq,Opt>::make(beta,S,Nmax), t);
+    return make_gf(mesh<imfreq,Opt>(beta,S,Nmax), t);
    }
   };
  } // gfs_implementation 
diff --git a/triqs/gfs/imtime.hpp b/triqs/gfs/imtime.hpp
index 79377453..bc0ff677 100644
--- a/triqs/gfs/imtime.hpp
+++ b/triqs/gfs/imtime.hpp
@@ -30,21 +30,20 @@ namespace triqs { namespace gfs {
 
  struct imtime {};
 
+ // mesh type and its factories
+ template<typename Opt> struct mesh<imtime,Opt> : linear_mesh<matsubara_domain<false>> {
+  typedef linear_mesh<matsubara_domain<false>> B;
+  mesh() = default;
+  mesh (double beta, statistic_enum S, size_t n_time_slices, mesh_kind mk=half_bins):
+   B( typename B::domain_t(beta,S), 0, beta, n_time_slices, mk){}
+ };
+
  namespace gfs_implementation { 
 
-  // mesh type and its factories
-  template<typename Opt> struct mesh<imtime,Opt> {
-   typedef linear_mesh<matsubara_domain<false>> type;
-   typedef typename type::domain_t domain_t;
-   static type make(double beta, statistic_enum S, size_t n_time_slices, mesh_kind mk=half_bins) {
-    return type(domain_t(beta,S), 0, beta, n_time_slices, mk);
-   }
-  };
- 
   // singularity 
   template<typename Opt> struct singularity<imtime,matrix_valued,Opt>  { typedef local::tail type;};
   template<typename Opt> struct singularity<imtime,scalar_valued,Opt>  { typedef local::tail type;};
-  
+
   // h5 name
   template<typename Opt> struct h5_name<imtime,matrix_valued,Opt>      { static std::string invoke(){ return  "ImTime";}};
 
@@ -53,7 +52,7 @@ namespace triqs { namespace gfs {
   template<typename Opt> struct data_proxy<imtime,matrix_valued,Opt> : data_proxy_array<double,3> {};
   template<typename Opt> struct data_proxy<imtime,scalar_valued,Opt> : data_proxy_array<double,1> {};
 
-   /// ---------------------------  closest mesh point on the grid ---------------------------------
+  /// ---------------------------  closest mesh point on the grid ---------------------------------
 
   template<typename Opt, typename Target>
    struct get_closest_point <imtime,Target,Opt> {
@@ -123,7 +122,7 @@ namespace triqs { namespace gfs {
       typename G::singularity_t const & operator()(G const * g,freq_infty const &) const {return g->singularity();}
    };
 
- // -------------------------------   Factories  --------------------------------------------------
+  // -------------------------------   Factories  --------------------------------------------------
 
   // matrix_valued
   template<typename Opt> struct factories<imtime,matrix_valued,Opt> { 
@@ -135,10 +134,10 @@ namespace triqs { namespace gfs {
      return gf_t (std::forward<MeshType>(m), std::move(A), t, nothing(), evaluator<imtime,matrix_valued,Opt>(shape[0],shape[1]) ) ;
     }
    static gf_t make_gf(double beta, statistic_enum S,  tqa::mini_vector<size_t,2> shape, size_t Nmax=1025, mesh_kind mk= half_bins) {
-    return make_gf(mesh<imtime,Opt>::make(beta,S,Nmax,mk), shape, local::tail(shape));
+    return make_gf(mesh<imtime,Opt>(beta,S,Nmax,mk), shape, local::tail(shape));
    }
    static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape, size_t Nmax, mesh_kind mk, local::tail_view const & t) {
-    return make_gf(mesh<imtime,Opt>::make(beta,S,Nmax,mk), shape, t);
+    return make_gf(mesh<imtime,Opt>(beta,S,Nmax,mk), shape, t);
    }
   };
 
@@ -151,14 +150,14 @@ namespace triqs { namespace gfs {
      return gf_t (std::forward<MeshType>(m), std::move(A), t, nothing());
     }
    static gf_t make_gf(double beta, statistic_enum S, size_t Nmax=1025, mesh_kind mk= half_bins) {
-    return make_gf(mesh<imtime,Opt>::make(beta,S,Nmax,mk), local::tail(tqa::mini_vector<size_t,2> (1,1)));
+    return make_gf(mesh<imtime,Opt>(beta,S,Nmax,mk), local::tail(tqa::mini_vector<size_t,2> (1,1)));
    }
    static gf_t make_gf(double beta, statistic_enum S, size_t Nmax, mesh_kind mk, local::tail_view const & t) {
-    return make_gf(mesh<imtime,Opt>::make(beta,S,Nmax,mk), t);
+    return make_gf(mesh<imtime,Opt>(beta,S,Nmax,mk), t);
    }
   };
  } // gfs_implementation.
- 
+
 }}
 #endif
 
diff --git a/triqs/gfs/legendre.hpp b/triqs/gfs/legendre.hpp
index 53b6b1d5..10df5fc0 100644
--- a/triqs/gfs/legendre.hpp
+++ b/triqs/gfs/legendre.hpp
@@ -30,15 +30,15 @@ namespace triqs { namespace gfs {
 
  struct legendre {};
 
+ // mesh type and its factories
+ template<typename Opt> struct mesh<legendre,Opt> :discrete_mesh<legendre_domain> { 
+  typedef discrete_mesh<legendre_domain> B;
+  mesh() = default;
+  mesh(double beta, statistic_enum S, size_t n_leg) : B(typename B::domain_t(beta,S,n_leg)) {}
+ };
+
  namespace gfs_implementation { 
 
-  // mesh type and its factories
-  template<typename Opt> struct mesh<legendre,Opt> { 
-   typedef discrete_mesh<legendre_domain> type;
-   typedef typename type::domain_t domain_t;
-   static type make(double beta, statistic_enum S, size_t n_leg) { return type(domain_t(beta,S,n_leg)); }
-  };
-  
   // h5 name
   template<typename Opt> struct h5_name<legendre,matrix_valued,Opt>      { static std::string invoke(){ return  "Legendre";}};
 
@@ -66,7 +66,7 @@ namespace triqs { namespace gfs {
 
    static gf_t make_gf(double beta, statistic_enum S, tqa::mini_vector<size_t,2> shape, size_t n_leg) {
     typename gf_t::data_regular_t A(shape.front_append(n_leg)); A() = 0;
-    return gf_t(mesh<legendre,Opt>::make(beta, S, n_leg), std::move(A), nothing(), nothing());
+    return gf_t(mesh<legendre,Opt>(beta, S, n_leg), std::move(A), nothing(), nothing());
    }
 
   };
diff --git a/triqs/gfs/meshes/linear.hpp b/triqs/gfs/meshes/linear.hpp
index 470a979c..1daaf93b 100644
--- a/triqs/gfs/meshes/linear.hpp
+++ b/triqs/gfs/meshes/linear.hpp
@@ -116,6 +116,7 @@ namespace triqs { namespace gfs {
 
    /// Mesh comparison
    bool operator == (linear_mesh const & M) const { return ((_dom == M._dom) && (size() ==M.size()) && (std::abs(xmin - M.xmin)<1.e-15) && (std::abs(xmax - M.xmax)<1.e-15));} 
+   bool operator != (linear_mesh const & M) const { return !(operator==(M));}
 
    /// Write into HDF5
    friend void h5_write (h5::group fg, std::string subgroup_name, linear_mesh const & m) {
diff --git a/triqs/gfs/product.hpp b/triqs/gfs/product.hpp
index 93b1110a..56b8f447 100644
--- a/triqs/gfs/product.hpp
+++ b/triqs/gfs/product.hpp
@@ -31,13 +31,14 @@ namespace triqs { namespace gfs {
   static constexpr size_t size = sizeof...(Ms); 
  };
 
+ // the mesh is simply a cartesian product
+ template<typename Opt, typename ... Ms> struct mesh<cartesian_product<Ms...>,Opt> : mesh_product< mesh<Ms,Opt> ... > { 
+  typedef mesh_product< mesh<Ms,Opt> ... > B;
+  typedef std::tuple<Ms...> mesh_name_t;
+  mesh (mesh<Ms,Opt> ... ms) : B {std::move(ms)...} {} 
+ };
+
  namespace gfs_implementation { 
-  // the mesh is simply a cartesian product
-  template<typename Opt, typename ... Ms> struct mesh<cartesian_product<Ms...>,Opt>  { 
-   typedef mesh_product< typename mesh<Ms,Opt>::type ... > type;
-   typedef std::tuple<Ms...> mesh_name_t;
-   static type make (typename mesh<Ms,Opt>::type ... ms) { return type{std::move(ms)...};} 
-  };
 
   // h5 name : name1_x_name2_.....
   template<typename Opt, typename ... Ms> struct h5_name<cartesian_product<Ms...>,matrix_valued,Opt>  { 
@@ -159,7 +160,7 @@ namespace triqs { namespace gfs {
 
     template<typename ... Meshes>
      static gf_t make_gf(Meshes && ... meshes) { 
-      auto m =  make_gf_mesh<cartesian_product<Ms...>,Opt>(meshes...);
+      auto m =  mesh<cartesian_product<Ms...>,Opt>(meshes...);
       typename gf_t::data_regular_t A(m.size()); 
       A() =0;
       return gf_t (m, std::move(A), nothing(), nothing());
diff --git a/triqs/gfs/re_im_freq.hpp b/triqs/gfs/re_im_freq.hpp
index feb319e1..bb11fc41 100644
--- a/triqs/gfs/re_im_freq.hpp
+++ b/triqs/gfs/re_im_freq.hpp
@@ -29,61 +29,60 @@
 namespace triqs { namespace gfs { 
   
   struct re_im_freq {};
-  
+
+  // the mesh
+  template<typename Opt> struct mesh<re_im_freq,Opt> : mesh_product<mesh<refreq,Opt>,mesh<imfreq,Opt>>  { 
+   typedef mesh<refreq,Opt> m1_t; 
+   typedef mesh<imfreq,Opt> m2_t; 
+   typedef mesh_product<m1_t,m2_t> B;
+   mesh (double wmin, double wmax, size_t n_freq_re, double beta, statistic_enum S, size_t n_freq_im) :
+    B { mesh<refreq,Opt>(wmin,wmax,n_freq_re,full_bins), mesh<imfreq,Opt>(beta, S, n_freq_im)} {}
+  };
+
   namespace gfs_implementation {
-    
-    // the mesh
-    template<typename Opt> struct mesh<re_im_freq,Opt>  { 
-      typedef typename mesh<refreq,Opt>::type m1_t; 
-      typedef typename mesh<imfreq,Opt>::type m2_t; 
-      typedef mesh_product<m1_t,m2_t> type;
-      static type make (double wmin, double wmax, size_t n_freq_re, double beta, statistic_enum S, size_t n_freq_im) { 
-        return {gfs::make_gf_mesh<refreq,Opt>(wmin,wmax,n_freq_re,full_bins), make_gf_mesh<imfreq,Opt>(beta, S, n_freq_im)};
-      }
-    };
-    
-    // singularity
-    template<typename Opt> struct singularity<re_im_freq,scalar_valued,Opt>  { typedef gf<refreq,scalar_valued> type;};
-    
-    // h5 name
-    template<typename Opt> struct h5_name<re_im_freq,scalar_valued,Opt> { static std::string invoke(){ return  "GfReImFreq";}};
-    
-    /// ---------------------------  data access  ---------------------------------
-    
-    template<typename Opt> struct data_proxy<re_im_freq,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
-    
-    /// ---------------------------  evaluator ---------------------------------  
-    
-    template<typename Opt>
+
+   // singularity
+   template<typename Opt> struct singularity<re_im_freq,scalar_valued,Opt>  { typedef gf<refreq,scalar_valued> type;};
+
+   // h5 name
+   template<typename Opt> struct h5_name<re_im_freq,scalar_valued,Opt> { static std::string invoke(){ return  "GfReImFreq";}};
+
+   /// ---------------------------  data access  ---------------------------------
+
+   template<typename Opt> struct data_proxy<re_im_freq,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
+
+   /// ---------------------------  evaluator ---------------------------------  
+
+   template<typename Opt>
     struct evaluator<re_im_freq,scalar_valued,Opt> {
-      static constexpr int arity = 2;
-      template<typename G>
+     static constexpr int arity = 2;
+     template<typename G>
       std::complex<double> operator() (G const * g, double w, long n)  const {
-        auto & data = g->data();
-        auto & mesh = g->mesh();
-        size_t nr; double wr; bool in;
-        std::tie(in, nr, wr) = windowing( std::get<0>(g->mesh().components()), w);
-        if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
-        auto gg = [g,data,mesh]( size_t nr, size_t n) {return data(mesh.index_to_linear(std::tuple<size_t,size_t>{nr,n}));};
-        return wr * gg(nr,n) + (1-wr) * gg(nr+1,n) ;
+       auto & data = g->data();
+       auto & mesh = g->mesh();
+       size_t nr; double wr; bool in;
+       std::tie(in, nr, wr) = windowing( std::get<0>(g->mesh().components()), w);
+       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
+       auto gg = [g,data,mesh]( size_t nr, size_t n) {return data(mesh.index_to_linear(std::tuple<size_t,size_t>{nr,n}));};
+       return wr * gg(nr,n) + (1-wr) * gg(nr+1,n) ;
       } 
     };
-    
-    // -------------------------------   Factories  --------------------------------------------------
-    
-    template<typename Opt> struct factories<re_im_freq, scalar_valued,Opt> {
-      typedef gf<re_im_freq, scalar_valued,Opt> gf_t;
-//       typedef typename mesh<re_im_freq, Opt>::type mesh_t;
-      
-      static gf_t make_gf(double wmin, double wmax, size_t nw, double beta, statistic_enum S, size_t nwn) { 
-        auto m =  make_gf_mesh<re_im_freq,Opt>(wmin, wmax, nw, beta, S, nwn);
-        typename gf_t::data_regular_t A(m.size()); 
-        A() =0;
-        return gf_t (m, std::move(A), gfs::make_gf<refreq,scalar_valued>(wmin, wmax, nw), nothing() ) ;
-      }
-    };
-    
-} // gfs_implementation
+
+   // -------------------------------   Factories  --------------------------------------------------
+
+   template<typename Opt> struct factories<re_im_freq, scalar_valued,Opt> {
+    typedef gf<re_im_freq, scalar_valued,Opt> gf_t;
+    //       typedef typename mesh<re_im_freq, Opt>::type mesh_t;
+
+    static gf_t make_gf(double wmin, double wmax, size_t nw, double beta, statistic_enum S, size_t nwn) { 
+     auto m =  mesh<re_im_freq,Opt>(wmin, wmax, nw, beta, S, nwn);
+     typename gf_t::data_regular_t A(m.size()); 
+     A() =0;
+     return gf_t (m, std::move(A), gfs::make_gf<refreq,scalar_valued>(wmin, wmax, nw), nothing() ) ;
+    }
+   };
+
+  } // gfs_implementation
 
 }}
 #endif
diff --git a/triqs/gfs/re_im_time.hpp b/triqs/gfs/re_im_time.hpp
index 031f64ae..198720ac 100644
--- a/triqs/gfs/re_im_time.hpp
+++ b/triqs/gfs/re_im_time.hpp
@@ -27,20 +27,19 @@
 #include "./meshes/product.hpp"
 
 namespace triqs { namespace gfs { 
-  
+
  struct re_im_time {};
 
- namespace gfs_implementation { 
+ // the mesh
+ template<typename Opt> struct mesh<re_im_time,Opt> :   mesh_product<mesh<retime,Opt>,mesh<imtime,Opt>>  { 
+  typedef mesh<retime,Opt> m1_t; 
+  typedef mesh<imtime,Opt> m2_t; 
+  typedef mesh_product<m1_t,m2_t> B;
+  mesh (double tmin, double tmax, size_t nt, double beta, statistic_enum S, size_t ntau, mesh_kind mk=full_bins) :
+   B {mesh<retime,Opt>(tmin,tmax,nt), mesh<imtime,Opt>(beta,S, ntau, mk)} {}
+ };
 
-  // the mesh
-  template<typename Opt> struct mesh<re_im_time,Opt>  { 
-   typedef typename mesh<retime,Opt>::type m1_t; 
-   typedef typename mesh<imtime,Opt>::type m2_t; 
-   typedef mesh_product<m1_t,m2_t> type;
-   static type make (double tmin, double tmax, size_t nt, double beta, statistic_enum S, size_t ntau, mesh_kind mk=full_bins) { 
-    return {make_gf_mesh<retime,Opt>(tmin,tmax,nt), make_gf_mesh<imtime,Opt>(beta,S, ntau, mk)};
-   }
-  };
+ namespace gfs_implementation { 
 
   // singularity
   //template<typename Opt> struct singularity<re_im_time, scalar_valued, Opt>  { typedef gf<retime,scalar_valued> type;};
@@ -78,16 +77,16 @@ namespace triqs { namespace gfs {
 
   template<typename Opt> struct factories<re_im_time, scalar_valued,Opt> {
    typedef gf<re_im_time, scalar_valued,Opt> gf_t;
-   
+
    template<typename MeshType>
-   static gf_t make_gf(MeshType && m) {
-    typename gf_t::data_regular_t A(m.size());
-    A() =0;
-    return gf_t (m, std::move(A), nothing(), nothing() ) ;
-   }
+    static gf_t make_gf(MeshType && m) {
+     typename gf_t::data_regular_t A(m.size());
+     A() =0;
+     return gf_t (m, std::move(A), nothing(), nothing() ) ;
+    }
 
    static gf_t make_gf(double tmin, double tmax, size_t nt, double beta, statistic_enum S, size_t ntau, mesh_kind mk=full_bins) { 
-    auto m =  make_gf_mesh<re_im_time,Opt>(tmin,tmax, nt, beta, S, ntau, mk);
+    auto m =  mesh<re_im_time,Opt>(tmin,tmax, nt, beta, S, ntau, mk);
     typename gf_t::data_regular_t A(m.size()); 
     A() =0;
     return gf_t (m, std::move(A), nothing(), nothing());
diff --git a/triqs/gfs/refreq.hpp b/triqs/gfs/refreq.hpp
index c2d2184f..35ca842e 100644
--- a/triqs/gfs/refreq.hpp
+++ b/triqs/gfs/refreq.hpp
@@ -30,20 +30,19 @@ namespace triqs { namespace gfs {
 
  struct refreq {};
 
+ template<typename Opt> struct mesh<refreq,Opt> : linear_mesh<R_domain> {
+  typedef linear_mesh<R_domain> B;
+  mesh() = default;
+  mesh (double wmin, double wmax, size_t n_freq, mesh_kind mk=full_bins) : 
+   B(typename B::domain_t(), wmin, wmax, n_freq, mk){}
+ };
+
  namespace gfs_implementation { 
-  
-  template<typename Opt> struct mesh<refreq,Opt>                { 
-   typedef linear_mesh<R_domain> type;
-   typedef typename type::domain_t domain_t;
-   static type make(double wmin, double wmax, size_t n_freq, mesh_kind mk=full_bins) {
-    return type(domain_t(), wmin, wmax, n_freq, mk);
-   }
-  };
-  
+
   // singularity 
   template<typename Opt> struct singularity<refreq,matrix_valued,Opt>  { typedef local::tail type;};
   template<typename Opt> struct singularity<refreq,scalar_valued,Opt>  { typedef local::tail type;};
-  
+
   // h5 name
   template<typename Opt> struct h5_name<refreq,matrix_valued,Opt>      { static std::string invoke(){ return "ReFreq";}};
 
@@ -54,67 +53,67 @@ namespace triqs { namespace gfs {
     typedef typename std::conditional < std::is_same<Target, matrix_valued>::value, arrays::matrix<std::complex<double> >, std::complex<double>>::type rtype; 
     template<typename G>
      rtype operator() (G const * g,double w0)  const {
-     //auto operator() (G const * g,double w0) const -> typename decltype ((*g)[0])::regular_type {
+      //auto operator() (G const * g,double w0) const -> typename decltype ((*g)[0])::regular_type {
       size_t n; double w; bool in;
       std::tie(in, n, w) = windowing(g->mesh(),w0);
       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
       auto gg = on_mesh(*g);
       return (1-w) * gg(n) + w * gg(n+1);
      }
-    template<typename G>
-     local::tail_view operator()(G const * g,freq_infty const &) const {return g->singularity();}
-   };
-   
-  /// ---------------------------  data access  ---------------------------------
-  template<typename Opt> struct data_proxy<refreq,matrix_valued,Opt> : data_proxy_array<std::complex<double>,3> {};
-  template<typename Opt> struct data_proxy<refreq,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
-   
-  // -------------------------------   Factories  --------------------------------------------------
-  
-  //matrix_valued
-  template<typename Opt> struct factories<refreq, matrix_valued,Opt> {
-   typedef gf<refreq,matrix_valued> gf_t;
+     template<typename G>
+      local::tail_view operator()(G const * g,freq_infty const &) const {return g->singularity();}
+     };
 
-   template<typename MeshType>
-    static gf_t make_gf(MeshType && m, tqa::mini_vector<size_t,2> shape, local::tail_view const & t) {
-     typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
-     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-    }
+    /// ---------------------------  data access  ---------------------------------
+    template<typename Opt> struct data_proxy<refreq,matrix_valued,Opt> : data_proxy_array<std::complex<double>,3> {};
+    template<typename Opt> struct data_proxy<refreq,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
 
-   static gf_t make_gf(double wmin, double wmax, size_t n_freq, tqa::mini_vector<size_t,2> shape) {
-    typename gf_t::data_regular_t A(shape.front_append(n_freq)); A() =0;
-    return gf_t(mesh<refreq,Opt>::make(wmin, wmax, n_freq, full_bins), std::move(A), local::tail(shape), nothing());
-   }
+    // -------------------------------   Factories  --------------------------------------------------
 
-   static gf_t make_gf(double wmin, double wmax, size_t n_freq, tqa::mini_vector<size_t,2> shape, mesh_kind mk) {
-    typename gf_t::data_regular_t A(shape.front_append(n_freq)); A() =0;
-    return gf_t(mesh<refreq,Opt>::make(wmin, wmax, n_freq, mk), std::move(A), local::tail(shape), nothing());
-   }
-  };
-   
-   //scalar_valued
-  template<typename Opt> struct factories<refreq,scalar_valued,Opt> {
-   typedef gf<refreq,scalar_valued> gf_t;
+    //matrix_valued
+    template<typename Opt> struct factories<refreq, matrix_valued,Opt> {
+     typedef gf<refreq,matrix_valued> gf_t;
 
-   template<typename MeshType>
-    static gf_t make_gf(MeshType && m, local::tail_view const & t) {
-     typename gf_t::data_regular_t A(m.size()); A() =0;
-     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-    }
-    
-    static gf_t make_gf(double wmin, double wmax, size_t n_freq) {
-     typename gf_t::data_regular_t A(n_freq); A() =0;
-     return gf_t(mesh<refreq,Opt>::make(wmin, wmax, n_freq), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
-    }
+     template<typename MeshType>
+      static gf_t make_gf(MeshType && m, tqa::mini_vector<size_t,2> shape, local::tail_view const & t) {
+       typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
+       return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
+      }
 
-   static gf_t make_gf(double wmin, double wmax, size_t n_freq, mesh_kind mk) {
-    typename gf_t::data_regular_t A(n_freq); A() =0;
-    return gf_t(mesh<refreq,Opt>::make(wmin, wmax, n_freq, mk), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
-   }
+     static gf_t make_gf(double wmin, double wmax, size_t n_freq, tqa::mini_vector<size_t,2> shape) {
+      typename gf_t::data_regular_t A(shape.front_append(n_freq)); A() =0;
+      return gf_t(mesh<refreq,Opt>(wmin, wmax, n_freq, full_bins), std::move(A), local::tail(shape), nothing());
+     }
 
-  };
- } // gfs_implementation
+     static gf_t make_gf(double wmin, double wmax, size_t n_freq, tqa::mini_vector<size_t,2> shape, mesh_kind mk) {
+      typename gf_t::data_regular_t A(shape.front_append(n_freq)); A() =0;
+      return gf_t(mesh<refreq,Opt>(wmin, wmax, n_freq, mk), std::move(A), local::tail(shape), nothing());
+     }
+    };
 
-}}
+    //scalar_valued
+    template<typename Opt> struct factories<refreq,scalar_valued,Opt> {
+     typedef gf<refreq,scalar_valued> gf_t;
+
+     template<typename MeshType>
+      static gf_t make_gf(MeshType && m, local::tail_view const & t) {
+       typename gf_t::data_regular_t A(m.size()); A() =0;
+       return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
+      }
+
+     static gf_t make_gf(double wmin, double wmax, size_t n_freq) {
+      typename gf_t::data_regular_t A(n_freq); A() =0;
+      return gf_t(mesh<refreq,Opt>(wmin, wmax, n_freq), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
+     }
+
+     static gf_t make_gf(double wmin, double wmax, size_t n_freq, mesh_kind mk) {
+      typename gf_t::data_regular_t A(n_freq); A() =0;
+      return gf_t(mesh<refreq,Opt>(wmin, wmax, n_freq, mk), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
+     }
+
+    };
+   } // gfs_implementation
+
+ }}
 #endif
 
diff --git a/triqs/gfs/refreq_imtime.hpp b/triqs/gfs/refreq_imtime.hpp
index b2970b65..b35cd3c4 100644
--- a/triqs/gfs/refreq_imtime.hpp
+++ b/triqs/gfs/refreq_imtime.hpp
@@ -27,78 +27,76 @@
 #include "./meshes/product.hpp"
 
 namespace triqs { namespace gfs {
-  
-  struct refreq_imtime {};
-  
-  namespace gfs_implementation { 
-    
-    // the mesh
-    template<typename Opt> struct mesh<refreq_imtime,Opt>  {
-      typedef typename mesh<refreq,Opt>::type m1_t; 
-      typedef typename mesh<imtime,Opt>::type m2_t; 
-      typedef mesh_product<m1_t,m2_t> type;
-      static type make (double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins ) { 
-        return {make_gf_mesh<refreq,Opt>(wmin,wmax,n_freq), make_gf_mesh<imtime,Opt>(beta,S,nt,mk)};
-      }
-    };
-    
-    // singularity
-    //template<typename Opt> struct singularity<refreq_imtime,scalar_valued,Opt>  { typedef gf<retime,scalar_valued> type;};
-    
-    // h5 name
-    template<typename Opt> struct h5_name<refreq_imtime,scalar_valued,Opt> { static std::string invoke(){ return  "GfReFreqImTime";}};
-    
-    /// ---------------------------  data access  ---------------------------------
-    
-    template<typename Opt> struct data_proxy<refreq_imtime,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
-    
-    /// ---------------------------  evaluator ---------------------------------
-    
-    template<typename Opt>
-    struct evaluator<refreq_imtime,scalar_valued,Opt> {
-      static constexpr int arity = 2;
-      template<typename G>
-      std::complex<double> operator() (G const * g, double omega, double tau)  const {
-       double beta = std::get<1>(g->mesh().components()).domain().beta;
-       int p = std::floor(tau/beta);
-       tau -= p*beta;
-       size_t n1,n2; double w1,w2; bool in;
-       std::tie(in, n1, w1) = windowing( std::get<0>(g->mesh().components()),omega);
-       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
-       std::tie(in, n2, w2) = windowing( std::get<1>(g->mesh().components()),tau);
-       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
-       auto gg = on_mesh(*g); //[g]( size_t n1, size_t n2) {return g->on_mesh(n1,n2);};
-       auto res =  w1 *( w2*gg(n1,n2) + (1-w2)*gg(n1,n2+1)) + (1-w1) * ( w2*gg(n1+1,n2) + (1-w2)*gg(n1+1,n2+1));
-   
-       //std::cout  << "eval reref imtim"<< n1 << " "<< n2 << " "<< w1 << " " << w2 << " "<< omega << " "<< tau<<  std::endl;
 
-       return ((std::get<1>(g->mesh().components()).domain().statistic == Fermion) && (p%2==1) ? -res : res);
-      } 
-    };
+ struct refreq_imtime {};
 
-    // -------------------------------   Factories  --------------------------------------------------
+ // the mesh
+ template<typename Opt> struct mesh<refreq_imtime,Opt> :mesh_product<mesh<refreq,Opt>,mesh<imtime,Opt>>  {
+  typedef mesh<refreq,Opt> m1_t; 
+  typedef mesh<imtime,Opt> m2_t; 
+  typedef mesh_product<m1_t,m2_t> B;
+  mesh (double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins ) :
+   B {mesh<refreq,Opt>(wmin,wmax,n_freq), mesh<imtime,Opt>(beta,S,nt,mk)} {}
+ };
 
-    template<typename Opt> struct factories<refreq_imtime, scalar_valued,Opt> {
-     typedef gf<refreq_imtime, scalar_valued,Opt> gf_t;
-     
-     template<typename MeshType>
-     static gf_t make_gf(MeshType && m) {
-      typename gf_t::data_regular_t A(m.size());
-      A() =0;
-      return gf_t (m, std::move(A), nothing(), nothing() ) ;
-     }
-     
-     static gf_t make_gf(double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins) { 
-      auto m =  make_gf_mesh<refreq_imtime,Opt>(wmin, wmax, n_freq, beta,S, nt, mk);
-      typename gf_t::data_regular_t A(m.size()); 
-      A() =0;
-      return gf_t (m, std::move(A), nothing(), nothing() ) ;
-     }
-    };
+ namespace gfs_implementation { 
+  // singularity
+  //template<typename Opt> struct singularity<refreq_imtime,scalar_valued,Opt>  { typedef gf<retime,scalar_valued> type;};
 
-  } // gfs_implementation
+  // h5 name
+  template<typename Opt> struct h5_name<refreq_imtime,scalar_valued,Opt> { static std::string invoke(){ return  "GfReFreqImTime";}};
 
-  //slices
+  /// ---------------------------  data access  ---------------------------------
+
+  template<typename Opt> struct data_proxy<refreq_imtime,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
+
+  /// ---------------------------  evaluator ---------------------------------
+
+  template<typename Opt>
+   struct evaluator<refreq_imtime,scalar_valued,Opt> {
+    static constexpr int arity = 2;
+    template<typename G>
+     std::complex<double> operator() (G const * g, double omega, double tau)  const {
+      double beta = std::get<1>(g->mesh().components()).domain().beta;
+      int p = std::floor(tau/beta);
+      tau -= p*beta;
+      size_t n1,n2; double w1,w2; bool in;
+      std::tie(in, n1, w1) = windowing( std::get<0>(g->mesh().components()),omega);
+      if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
+      std::tie(in, n2, w2) = windowing( std::get<1>(g->mesh().components()),tau);
+      if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
+      auto gg = on_mesh(*g); //[g]( size_t n1, size_t n2) {return g->on_mesh(n1,n2);};
+      auto res =  w1 *( w2*gg(n1,n2) + (1-w2)*gg(n1,n2+1)) + (1-w1) * ( w2*gg(n1+1,n2) + (1-w2)*gg(n1+1,n2+1));
+
+      //std::cout  << "eval reref imtim"<< n1 << " "<< n2 << " "<< w1 << " " << w2 << " "<< omega << " "<< tau<<  std::endl;
+
+      return ((std::get<1>(g->mesh().components()).domain().statistic == Fermion) && (p%2==1) ? -res : res);
+     } 
+   };
+
+  // -------------------------------   Factories  --------------------------------------------------
+
+  template<typename Opt> struct factories<refreq_imtime, scalar_valued,Opt> {
+   typedef gf<refreq_imtime, scalar_valued,Opt> gf_t;
+
+   template<typename MeshType>
+    static gf_t make_gf(MeshType && m) {
+     typename gf_t::data_regular_t A(m.size());
+     A() =0;
+     return gf_t (m, std::move(A), nothing(), nothing() ) ;
+    }
+
+   static gf_t make_gf(double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins) { 
+    auto m =  mesh<refreq_imtime,Opt>(wmin, wmax, n_freq, beta,S, nt, mk);
+    typename gf_t::data_regular_t A(m.size()); 
+    A() =0;
+    return gf_t (m, std::move(A), nothing(), nothing() ) ;
+   }
+  };
+
+ } // gfs_implementation
+
+ //slices
  inline gf_view<refreq,scalar_valued> slice_mesh_imtime (gf_view<refreq_imtime,scalar_valued> g, size_t index) { 
   auto arr = reinterpret_linear_array(g.mesh(),g.data()); // view it as a 2d array
   return { std::get<0>(g.mesh().components()), arr(arrays::range(),index), local::tail(1,1), nothing() };
diff --git a/triqs/gfs/retime.hpp b/triqs/gfs/retime.hpp
index e91b5354..bcb7b25a 100644
--- a/triqs/gfs/retime.hpp
+++ b/triqs/gfs/retime.hpp
@@ -30,22 +30,18 @@ namespace triqs { namespace gfs {
 
  struct retime {};
 
+ template<typename Opt> struct mesh<retime,Opt> : linear_mesh<R_domain>  { 
+  typedef linear_mesh<R_domain> B;
+  mesh() = default;
+  mesh(double tmin, double tmax, size_t n_points, mesh_kind mk=full_bins) : B (typename B::domain_t(), tmin, tmax, n_points, mk){}
+ };
+
  namespace gfs_implementation { 
 
-  template<typename Opt> struct mesh<retime,Opt> { 
-   typedef linear_mesh<R_domain> type;
-   typedef typename type::domain_t domain_t;
-
-   static type make(double tmin, double tmax, size_t n_points, mesh_kind mk=full_bins) {
-     return type(domain_t(), tmin, tmax, n_points, mk);
-   }
-   
-  };
-  
   // singularity 
   template<typename Opt> struct singularity<retime,matrix_valued,Opt>  { typedef local::tail type;};
   template<typename Opt> struct singularity<retime,scalar_valued,Opt>  { typedef local::tail type;};
-  
+
   // h5 name
   template<typename Opt> struct h5_name<retime,matrix_valued,Opt>      { static std::string invoke(){ return  "ReTime";}};
 
@@ -56,7 +52,7 @@ namespace triqs { namespace gfs {
     //typedef typename std::conditional < std::is_same<Target, matrix_valued>::value, arrays::matrix_view<std::complex<double>>, std::complex<double>>::type rtype; 
     typedef typename std::conditional < std::is_same<Target, matrix_valued>::value, arrays::matrix<std::complex<double>>, std::complex<double>>::type rtype; 
     template<typename G>
-      rtype operator() (G const * g,double t0)  const {
+     rtype operator() (G const * g,double t0)  const {
       size_t n; double w; bool in;
       std::tie(in, n, w) = windowing(g->mesh(),t0);
       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
@@ -68,56 +64,56 @@ namespace triqs { namespace gfs {
    };
 
   /// ---------------------------  data access  ---------------------------------
-   template<typename Opt> struct data_proxy<retime,matrix_valued,Opt> : data_proxy_array<std::complex<double>,3> {};
-   template<typename Opt> struct data_proxy<retime,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
+  template<typename Opt> struct data_proxy<retime,matrix_valued,Opt> : data_proxy_array<std::complex<double>,3> {};
+  template<typename Opt> struct data_proxy<retime,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
 
   // -------------------------------   Factories  --------------------------------------------------
 
   //matrix_valued
   template<typename Opt> struct factories<retime, matrix_valued,Opt> {
    typedef gf<retime,matrix_valued> gf_t;
-   
+
    template<typename MeshType>
-   static gf_t make_gf(MeshType && m, tqa::mini_vector<size_t,2> shape, local::tail_view const t) {
-    typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
-    return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-   }
-   
+    static gf_t make_gf(MeshType && m, tqa::mini_vector<size_t,2> shape, local::tail_view const t) {
+     typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
+     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
+    }
+
    static gf_t make_gf(double tmin, double tmax, size_t n_points, tqa::mini_vector<size_t,2> shape, mesh_kind mk) {
     typename gf_t::data_regular_t A(shape.front_append(n_points)); A() =0;
-    return gf_t(mesh<retime,Opt>::make(tmin, tmax, n_points,mk), std::move(A), local::tail(shape), nothing());
+    return gf_t(mesh<retime,Opt>(tmin, tmax, n_points,mk), std::move(A), local::tail(shape), nothing());
    }
-   
+
    static gf_t make_gf(double tmin, double tmax, size_t n_points, tqa::mini_vector<size_t,2> shape) {
     typename gf_t::data_regular_t A(shape.front_append(n_points)); A() =0;
-    return gf_t(mesh<retime,Opt>::make(tmin, tmax, n_points), std::move(A), local::tail(shape), nothing());
+    return gf_t(mesh<retime,Opt>(tmin, tmax, n_points), std::move(A), local::tail(shape), nothing());
    }
-   
+
   };
-  
+
   //scalar_valued
   template<typename Opt> struct factories<retime, scalar_valued,Opt> {
    typedef gf<retime,scalar_valued> gf_t;
-   
+
    template<typename MeshType>
-   static gf_t make_gf(MeshType && m, local::tail_view const t) {
-    typename gf_t::data_regular_t A(m.size()); A() =0;
-    return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
-   }
-   
+    static gf_t make_gf(MeshType && m, local::tail_view const t) {
+     typename gf_t::data_regular_t A(m.size()); A() =0;
+     return gf_t ( std::forward<MeshType>(m), std::move(A), t, nothing() ) ;
+    }
+
    static gf_t make_gf(double tmin, double tmax, size_t n_points, mesh_kind mk) {
     typename gf_t::data_regular_t A(n_points); A() =0;
-    return gf_t(mesh<retime,Opt>::make(tmin, tmax, n_points,mk), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
+    return gf_t(mesh<retime,Opt>(tmin, tmax, n_points,mk), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
    }
-   
+
    static gf_t make_gf(double tmin, double tmax, size_t n_points) {
     typename gf_t::data_regular_t A(n_points); A() =0;
-    return gf_t(mesh<retime,Opt>::make(tmin, tmax, n_points), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
+    return gf_t(mesh<retime,Opt>(tmin, tmax, n_points), std::move(A), local::tail(tqa::mini_vector<size_t,2>(1,1)), nothing());
    }
-   
+
   };
-  
-  
+
+
  } // gfs_implementation
 }}
 #endif
diff --git a/triqs/gfs/two_real_times.hpp b/triqs/gfs/two_real_times.hpp
index 513bef2d..b74567d7 100644
--- a/triqs/gfs/two_real_times.hpp
+++ b/triqs/gfs/two_real_times.hpp
@@ -29,24 +29,17 @@ namespace triqs { namespace gfs {
 
  struct two_real_times {};
 
+ // the mesh
+ template<typename Opt> struct mesh<two_real_times,Opt> :mesh_product<mesh<retime,Opt> ,mesh<retime,Opt> >  { 
+  typedef mesh_product<mesh<retime,Opt> ,mesh<retime,Opt> > B;
+  mesh() = default;
+  mesh (double tmax, double n_time_slices) :
+   B(mesh<retime,Opt> ( 0, tmax,n_time_slices, full_bins), 
+     mesh<retime,Opt> ( 0, tmax,n_time_slices, full_bins) ) {}
+ };
+
  namespace gfs_implementation { 
 
-  // the mesh
-  template<typename Opt> struct mesh<two_real_times,Opt>  { 
-   typedef typename mesh<retime,Opt>::type m1_t; 
-   typedef mesh_product<m1_t,m1_t> type;
-   static type make (double tmax, double n_time_slices) { 
-#ifndef TRIQS_WORKAROUND_INTEL_COMPILER_BUGS 
-    m1_t m1({},0, tmax,n_time_slices, full_bins);
-    return {m1,m1};
-#else
-    m1_t m1(typename m1_t::domain_t(),0, tmax,n_time_slices, full_bins);
-    type m(m1,m1);
-    return m; 
-#endif
-   }
-  };
-  
   // h5 name
   template<typename Opt> struct h5_name<two_real_times,matrix_valued,Opt> { static std::string invoke(){ return  "GfTwoRealTime";}};
 
@@ -54,23 +47,23 @@ namespace triqs { namespace gfs {
 
   template<typename Opt>
    struct get_closest_point <two_real_times,matrix_valued,Opt> {
-   typedef typename mesh<two_real_times, Opt>::type mesh_t;
-    
-//    // NOT FINISHED, NOT TESTED 
-//     template<typename G, typename T>
-//      static typename mesh_t::index_t invoke(G const * g, closest_pt_wrap<T,T> const & p) {
-//       return std::floor( double(p.value) / g->mesh().delta() + 0.5);
-//      }
+    typedef typename mesh<two_real_times, Opt>::type mesh_t;
+
+    //    // NOT FINISHED, NOT TESTED 
+    //     template<typename G, typename T>
+    //      static typename mesh_t::index_t invoke(G const * g, closest_pt_wrap<T,T> const & p) {
+    //       return std::floor( double(p.value) / g->mesh().delta() + 0.5);
+    //      }
 
    };
 
   /// ---------------------------  evaluator ---------------------------------
 
   template<typename Opt>
-  struct evaluator<two_real_times,matrix_valued,Opt> {
+   struct evaluator<two_real_times,matrix_valued,Opt> {
     static constexpr int arity = 2;
     template<typename G>
-    arrays::matrix<std::complex<double> > operator() (G const * g, double t0, double t1)  const {
+     arrays::matrix<std::complex<double> > operator() (G const * g, double t0, double t1)  const {
       auto & data = g->data();
       auto & m = std::get<0>(g->mesh().components()); 
       size_t n0,n1; double w0,w1; bool in;
@@ -80,8 +73,8 @@ namespace triqs { namespace gfs {
       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
       auto gg = [g,data]( size_t n0, size_t n1) {return data(g->mesh().index_to_linear(std::tuple<size_t,size_t>{n0,n1}), arrays::ellipsis());};
       return  w0 * ( w1*gg(n0,n1) + (1-w1)*gg(n0,n1+1) ) + (1-w0) * ( w1*gg(n0+1,n1) + (1-w1)*gg(n0+1,n1+1)); 
-    } 
-  };
+     } 
+   };
 
   /// ---------------------------  data access  ---------------------------------
 
@@ -91,10 +84,10 @@ namespace triqs { namespace gfs {
 
   template<typename Opt> struct factories<two_real_times, matrix_valued,Opt> {
    typedef gf<two_real_times, matrix_valued,Opt> gf_t;
-   typedef typename mesh<two_real_times, Opt>::type mesh_t;
+   typedef mesh<two_real_times, Opt> mesh_t;
 
    static gf_t make_gf(double tmax, double n_time_slices, tqa::mini_vector<size_t,2> shape) {
-    auto m =  mesh<two_real_times,Opt>::make(tmax, n_time_slices);
+    auto m =  mesh<two_real_times,Opt>(tmax, n_time_slices);
     typename gf_t::data_regular_t A(shape.front_append(m.size())); A() =0;
     return gf_t (m, std::move(A), nothing(), nothing() ) ;
    }
@@ -131,10 +124,10 @@ namespace triqs { namespace gfs {
 
  } // gfs_implementation
 
-  // -------------------------------   Additionnal free function for this gf  --------------------------------------------------
-  
-  // from g(t,t') and t, return g(t-t') for any t'>t 
-  // 
+ // -------------------------------   Additionnal free function for this gf  --------------------------------------------------
+
+ // from g(t,t') and t, return g(t-t') for any t'>t 
+ // 
  gf<retime> slice (gf_view<two_real_times> const & g, double t) { 
   auto const & m = std::get<0> (g.mesh().components());   //one-time mesh
   long it = get_closest_mesh_pt_index(m, t);              //index of t on this mesh