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 | |
|
Assertion | 3com13 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 3exp.1 | |
|
2 | 1 | 3exp | |
3 | 2 | 3imp31 | |