Metamath Proof Explorer


Theorem curryax

Description: A non-intuitionistic positive statement, sometimes called a paradox of material implication. Sometimes called Curry's axiom. Similar to exmid (obtained by substituting F. for ps ) but positive. For another non-intuitionistic positive statement, see peirce . (Contributed by BJ, 4-Apr-2021)

Ref Expression
Assertion curryax
|- ( ph \/ ( ph -> ps ) )

Proof

Step Hyp Ref Expression
1 pm2.21
 |-  ( -. ph -> ( ph -> ps ) )
2 1 orri
 |-  ( ph \/ ( ph -> ps ) )