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Description: Elimination of an antecedent. (Contributed by NM, 1-Jan-2005)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | pm2.61dan.1 | ⊢ ( ( 𝜑 ∧ 𝜓 ) → 𝜒 ) | |
| pm2.61dan.2 | ⊢ ( ( 𝜑 ∧ ¬ 𝜓 ) → 𝜒 ) | ||
| Assertion | pm2.61dan | ⊢ ( 𝜑 → 𝜒 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pm2.61dan.1 | ⊢ ( ( 𝜑 ∧ 𝜓 ) → 𝜒 ) | |
| 2 | pm2.61dan.2 | ⊢ ( ( 𝜑 ∧ ¬ 𝜓 ) → 𝜒 ) | |
| 3 | 1 | ex | ⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) ) |
| 4 | 2 | ex | ⊢ ( 𝜑 → ( ¬ 𝜓 → 𝜒 ) ) |
| 5 | 3 4 | pm2.61d | ⊢ ( 𝜑 → 𝜒 ) |