The gfs class of TRIQS contains objects representing Green functions over real or imaginary times, rela or imaginary frequencies... that can be easily manipulated.
(see :doc:`here <../../reference/c++/gf/contents>`).
Here are a couple of simple examples showing the basic use of this class.
Creation of a real time GF
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Here we create a GF define on the time interval from tmin to tmax.
If we want the value of the GF at any time to be a scalar, we use: