Let x0 of type ι be given.
Apply SNo_max_SNoLev with
x0,
λ x1 x2 . ordinal x1 leaving 3 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.
Apply SNoLev_ordinal with
x0.
The subproof is completed by applying H0.