Let x0 of type ο be given.
Assume H0: x0.
Apply unknownprop_e284d5f5a7c3a1c03631041619c4ddee06de72330506f5f6d9d6b18df929e48c with
not x0.
Apply notE with
x0 leaving 2 subgoals.
The subproof is completed by applying H1.
The subproof is completed by applying H0.