Metamath Proof Explorer


Theorem 3com13

Description: Commutation in antecedent. Swap 1st and 3rd. (Contributed by NM, 28-Jan-1996) (Proof shortened by Wolf Lammen, 22-Jun-2022)

Ref Expression
Hypothesis 3exp.1 φψχθ
Assertion 3com13 χψφθ

Proof

Step Hyp Ref Expression
1 3exp.1 φψχθ
2 1 3exp φψχθ
3 2 3imp31 χψφθ