A functional equation arising in multi-agent statistical decision theory.
The functional equation (F(x)-F(y))/(x-y) = (G(x)+G(y))(H(x)+H(y)) where F,G,H are unknown functions is considered. Some motivations, coming from the equality problem for means, are presented.
We first recall Malgrange’s definition of -groupoid and we define a Galois -groupoid for -difference equations. Then, we compute explicitly the Galois -groupoid of a constant linear -difference system, and show that it corresponds to the -difference Galois group. Finally, we establish a conjugation between the Galois -groupoids of two equivalent constant linear -difference systems, and define a local Galois -groupoid for Fuchsian linear -difference systems by giving its realizations.