Metamath Proof Explorer


Theorem com14

Description: Commutation of antecedents. Swap 1st and 4th. (Contributed by NM, 25-Apr-1994) (Proof shortened by Wolf Lammen, 28-Jul-2012)

Ref Expression
Hypothesis com4.1 φψχθτ
Assertion com14 θψχφτ

Proof

Step Hyp Ref Expression
1 com4.1 φψχθτ
2 1 com4l ψχθφτ
3 2 com3r θψχφτ