Description: Double commutation in conjunction. (Contributed by Peter Mazsa, 27-Jun-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | an2anr | ⊢ ( ( ( 𝜑 ∧ 𝜓 ) ∧ ( 𝜒 ∧ 𝜃 ) ) ↔ ( ( 𝜓 ∧ 𝜑 ) ∧ ( 𝜃 ∧ 𝜒 ) ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ancom | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ ( 𝜓 ∧ 𝜑 ) ) | |
| 2 | ancom | ⊢ ( ( 𝜒 ∧ 𝜃 ) ↔ ( 𝜃 ∧ 𝜒 ) ) | |
| 3 | 1 2 | anbi12i | ⊢ ( ( ( 𝜑 ∧ 𝜓 ) ∧ ( 𝜒 ∧ 𝜃 ) ) ↔ ( ( 𝜓 ∧ 𝜑 ) ∧ ( 𝜃 ∧ 𝜒 ) ) ) |