Metamath Proof Explorer


Theorem 19.32v

Description: Version of 19.32 with a disjoint variable condition, requiring fewer axioms. (Contributed by BJ, 7-Mar-2020)

Ref Expression
Assertion 19.32v xφψφxψ

Proof

Step Hyp Ref Expression
1 19.21v x¬φψ¬φxψ
2 df-or φψ¬φψ
3 2 albii xφψx¬φψ
4 df-or φxψ¬φxψ
5 1 3 4 3bitr4i xφψφxψ