fact: Definition toParamSym@{} : Param2a4.Rel@{i} B A := @Param2a4.BuildRel B A (sym_rel (graph f)) (@Map2a.BuildHas@{i} _ _ _ _ (section_in_retract)) (@Map4.BuildHas@{i} _ _ _ _ (fun _ _ => id) (fun _ _ => id) (fun _ _ _ => 1%path)).
imports: ssreflect