Description: Commutative law for a conjunction with a triple conjunction: second and forth positions interchanged. (Contributed by AV, 18-Feb-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | 3an4ancom24 | |- ( ( ( ph /\ ps /\ ch ) /\ th ) <-> ( ( ph /\ th /\ ch ) /\ ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | an4com24 | |- ( ( ( ph /\ ps ) /\ ( ch /\ th ) ) <-> ( ( ph /\ th ) /\ ( ch /\ ps ) ) ) |
|
2 | 3an4anass | |- ( ( ( ph /\ ps /\ ch ) /\ th ) <-> ( ( ph /\ ps ) /\ ( ch /\ th ) ) ) |
|
3 | 3an4anass | |- ( ( ( ph /\ th /\ ch ) /\ ps ) <-> ( ( ph /\ th ) /\ ( ch /\ ps ) ) ) |
|
4 | 1 2 3 | 3bitr4i | |- ( ( ( ph /\ ps /\ ch ) /\ th ) <-> ( ( ph /\ th /\ ch ) /\ ps ) ) |