Proofgold Proof

pf
Let x0 of type ι be given. Assume H0: ordinal x0. Apply ordinal_In_SNoLt with ordsucc x0, 0 leaving 2 subgoals. Apply ordinal_ordsucc with x0. The subproof is completed by applying H0. Apply ordinal_0_In_ordsucc with x0. The subproof is completed by applying H0. ■