Description: Corollary of commutation of and. (Contributed by RP, 25-Apr-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | ifpancor | ⊢ ( if- ( 𝜑 , 𝜓 , 𝜑 ) ↔ if- ( 𝜓 , 𝜑 , 𝜓 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ancom | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ ( 𝜓 ∧ 𝜑 ) ) | |
2 | ifpdfan2 | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ if- ( 𝜑 , 𝜓 , 𝜑 ) ) | |
3 | ifpdfan2 | ⊢ ( ( 𝜓 ∧ 𝜑 ) ↔ if- ( 𝜓 , 𝜑 , 𝜓 ) ) | |
4 | 1 2 3 | 3bitr3i | ⊢ ( if- ( 𝜑 , 𝜓 , 𝜑 ) ↔ if- ( 𝜓 , 𝜑 , 𝜓 ) ) |