Let x0 of type ι be given.
Let x1 of type ι → ο be given.
Assume H1: x1 0.
Assume H2:
∀ x2 . x1 x2 ⟶ x1 (ordsucc x2).
Apply H2 with
x0.
Apply H0 with
x1 leaving 2 subgoals.
The subproof is completed by applying H1.
The subproof is completed by applying H2.