Metamath Proof Explorer

Theorem com13

Description: Commutation of antecedents. Swap 1st and 3rd. (Contributed by NM, 25-Apr-1994) (Proof shortened by Wolf Lammen, 28-Jul-2012)

Ref Expression
Hypothesis com3.1 
|- ( ph -> ( ps -> ( ch -> th ) ) )
Assertion com13 
|- ( ch -> ( ps -> ( ph -> th ) ) )

Proof

Step Hyp Ref Expression
1 com3.1 
 |-  ( ph -> ( ps -> ( ch -> th ) ) )
2 1 com3r 
 |-  ( ch -> ( ph -> ( ps -> th ) ) )
3 2 com23 
 |-  ( ch -> ( ps -> ( ph -> th ) ) )