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Description: Existential elimination rule of natural deduction. (Contributed by ML, 17-Jul-2020) Shorten exlimdd . (Revised by Wolf Lammen, 3-Sep-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | exlimdd.1 | ⊢ Ⅎ 𝑥 𝜑 | |
| exlimdd.2 | ⊢ Ⅎ 𝑥 𝜒 | ||
| exlimdd.3 | ⊢ ( 𝜑 → ∃ 𝑥 𝜓 ) | ||
| exlimimdd.4 | ⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) ) | ||
| Assertion | exlimimdd | ⊢ ( 𝜑 → 𝜒 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | exlimdd.1 | ⊢ Ⅎ 𝑥 𝜑 | |
| 2 | exlimdd.2 | ⊢ Ⅎ 𝑥 𝜒 | |
| 3 | exlimdd.3 | ⊢ ( 𝜑 → ∃ 𝑥 𝜓 ) | |
| 4 | exlimimdd.4 | ⊢ ( 𝜑 → ( 𝜓 → 𝜒 ) ) | |
| 5 | 1 2 4 | exlimd | ⊢ ( 𝜑 → ( ∃ 𝑥 𝜓 → 𝜒 ) ) |
| 6 | 3 5 | mpd | ⊢ ( 𝜑 → 𝜒 ) |