fact: Hypotheses (f_op : forall x y : R2, valid (x \+ y) -> f (x \+ y) = op1 (f x) (f y)) (f_id : f Unit = id1).
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq bigop fintype finset) pcm(options axioms prelude seqperm pred seqext)