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Description: Introduction of a triple conjunct inside a contradiction. (Contributed by FL, 27-Dec-2007) (Proof shortened by Andrew Salmon, 26-Jun-2011)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | intn3and.1 | ⊢ ( 𝜑 → ¬ 𝜓 ) | |
| Assertion | intn3an2d | ⊢ ( 𝜑 → ¬ ( 𝜒 ∧ 𝜓 ∧ 𝜃 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | intn3and.1 | ⊢ ( 𝜑 → ¬ 𝜓 ) | |
| 2 | simp2 | ⊢ ( ( 𝜒 ∧ 𝜓 ∧ 𝜃 ) → 𝜓 ) | |
| 3 | 1 2 | nsyl | ⊢ ( 𝜑 → ¬ ( 𝜒 ∧ 𝜓 ∧ 𝜃 ) ) |