Hi PF(adsbygoogle = window.adsbygoogle || []).push({});

I try to understand how we get get a Taylor expansion of a non linear functional.

I found this good paper

here F maps functions to scalars. F[f] is defined. It has not scalars as arguments. I agree with A13 and A18.

In another paper (in french) skip to page 9

the fisrt term is ##\int dx P_0 (x)## and all the terms have one more variable.

Do you understand the second point of view? we did not start with densities.

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# B Functional derivative

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