fact: Definition OpAdd (o o': Op1) : option Op1 := match o with | Equal => Some o' | NonStrict => match o' with | Strict => Some Strict | NonEqual => None | _ => Some NonStrict end | Strict => match o' with | NonEqual => None | _ => Some Strict end | NonEqual => match o' with | Equal => Some NonEqual | _ => None end end.
imports: NArith Relation_Definitions Setoid Env EnvRing List Bool OrderedRing Refl