Proofgold Proof

pf
Let x0 of type ι be given. Let x1 of type ι be given. Assume H0: x0 = x1 ⟶ False. Assume H1: ordsucc x0 = ordsucc x1. Apply H0. Apply ordsucc_inj with x0, x1. The subproof is completed by applying H1. ■