proposition: Lemma graph_on_sr (r: relation) x: (forall a, inc a x -> r a a) -> substrate (graph_on r x) = x.
proof: Proof. move=> rr. apply: extensionality; first by apply: graph_on_sr1. move => t xt; move: (rr _ xt) => rtt. by apply: (arg1_sr (y:=t)); apply: Zo_i; [apply:setXp_i | aw]. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)