proposition: Lemma ex7_fij_prop1 i j: gle (isr S) i j -> function_prop (ex7_fij i j) (ex7_Ei i) (ex7_Ei j).
proof: Proof. move => lij; split. - move:(inl_prop0 lij) => [iI jI]. move:(ex7_eqv_prop1 iI) (ex7_eqv_prop1 jI) => [ha hb ][hc hd]. move: (inl_prop4 lij) => [fij sij tij]. have tij': target (Vg (isf S) (J i j)) = substrate (ex7_eqv j) by ue. have sij': source (Vg (isf S) (J i j)) = substrate (ex7_eqv i) by ue. by apply:foqcs_f. - by rewrite /ex7_fij /fun_on_quotients /section_canon_proj; aw. - by rewrite /ex7_fij /fun_on_quotients; aw. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)