Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι → ο be given.
Let x3 of type ι → ο be given.
Assume H0:
PNoLt x0 x2 x1 x3.
Apply orIL with
PNoLt x0 x2 x1 x3,
and (x0 = x1) (PNoEq_ x0 x2 x3).
The subproof is completed by applying H0.