Description: Swap two conjuncts in antecedent. The label suffix "s" means that an12 is combined with syl (or a variant). (Contributed by NM, 13-Mar-1996)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | an12s.1 | |- ( ( ph /\ ( ps /\ ch ) ) -> th ) |
|
| Assertion | an12s | |- ( ( ps /\ ( ph /\ ch ) ) -> th ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | an12s.1 | |- ( ( ph /\ ( ps /\ ch ) ) -> th ) |
|
| 2 | an12 | |- ( ( ps /\ ( ph /\ ch ) ) <-> ( ph /\ ( ps /\ ch ) ) ) |
|
| 3 | 2 1 | sylbi | |- ( ( ps /\ ( ph /\ ch ) ) -> th ) |