This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: Theorem *4.38 of WhiteheadRussell p. 118. (Contributed by NM, 3-Jan-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pm4.38 | ⊢ ( ( ( 𝜑 ↔ 𝜒 ) ∧ ( 𝜓 ↔ 𝜃 ) ) → ( ( 𝜑 ∧ 𝜓 ) ↔ ( 𝜒 ∧ 𝜃 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpl | ⊢ ( ( ( 𝜑 ↔ 𝜒 ) ∧ ( 𝜓 ↔ 𝜃 ) ) → ( 𝜑 ↔ 𝜒 ) ) | |
| 2 | simpr | ⊢ ( ( ( 𝜑 ↔ 𝜒 ) ∧ ( 𝜓 ↔ 𝜃 ) ) → ( 𝜓 ↔ 𝜃 ) ) | |
| 3 | 1 2 | anbi12d | ⊢ ( ( ( 𝜑 ↔ 𝜒 ) ∧ ( 𝜓 ↔ 𝜃 ) ) → ( ( 𝜑 ∧ 𝜓 ) ↔ ( 𝜒 ∧ 𝜃 ) ) ) |