Proofgold Proof

pf
Let x0 of type ο be given. Let x1 of type ο be given. Assume H0: not x0 ⟶ not x1. Assume H1: x1. Apply unknownprop_b777a79c17f16cd28153af063df26a4626b11c1f1d4394d7f537c11837ab0962 with x0. Assume H2: not x0. Apply notE with x1 leaving 2 subgoals. Apply H0. The subproof is completed by applying H2. The subproof is completed by applying H1. ■