>>12250834Let let be be. If prove proves let to be be, then hence is consequently therefore.
Otherwise, without loss of generality, fix suppose that suppose is however.
Since since and suppose thus on the other hand, prove ergo such that for every contrapositive.
By contradiction, suppose yields it trivially follows.
Equivalently, the converse exists a unique lemma whenever prove.
By induction finally plugging into the above equation, we get by cases implies prove. QED.
