Description: Define and with conditional logic operator and false. (Contributed by RP, 20-Apr-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ifpdfan | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ if- ( 𝜑 , 𝜓 , ⊥ ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fal | ⊢ ¬ ⊥ | |
| 2 | 1 | intnan | ⊢ ¬ ( ¬ 𝜑 ∧ ⊥ ) |
| 3 | 2 | biorfri | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ ( ( 𝜑 ∧ 𝜓 ) ∨ ( ¬ 𝜑 ∧ ⊥ ) ) ) |
| 4 | df-ifp | ⊢ ( if- ( 𝜑 , 𝜓 , ⊥ ) ↔ ( ( 𝜑 ∧ 𝜓 ) ∨ ( ¬ 𝜑 ∧ ⊥ ) ) ) | |
| 5 | 3 4 | bitr4i | ⊢ ( ( 𝜑 ∧ 𝜓 ) ↔ if- ( 𝜑 , 𝜓 , ⊥ ) ) |