fact: Definition Exercise6_32_conc A B k0:= exists f, [/\ bijection_prop f (unionb A) (unionb B), forall i x, intp i -> inc x (Vg A i) -> exists2 j, inc j (ZN_int i k0 k0) & inc (Vf f x) (Vg B j) & forall i x, intp i -> inc x (Vg B i) -> exists2 j, inc j (ZN_int i k0 k0) & inc (Vf (inverse_fun f) x) (Vg A j) ].
imports: mathcomp(ssreflect ssrbool ssrfun eqtype)