Nuprl Lemma : invert-union_wf 11,40

AB:Type, x:(A + B). invert-union(x (B + A
latex


ProofTree


Definitionsinvert-union(x), x:AB(x), case b of inl(x) => s(x) | inr(y) => t(y), inr x , inl x , left + right, t  T, Type

origin