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Description: Deduction rule for nonempty classes. (Contributed by Thierry Arnoux, 3-Aug-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | n0limd.1 | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | |
| n0limd.2 | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝜓 ) | ||
| Assertion | n0limd | ⊢ ( 𝜑 → 𝜓 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | n0limd.1 | ⊢ ( 𝜑 → 𝐴 ≠ ∅ ) | |
| 2 | n0limd.2 | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝜓 ) | |
| 3 | n0 | ⊢ ( 𝐴 ≠ ∅ ↔ ∃ 𝑥 𝑥 ∈ 𝐴 ) | |
| 4 | 1 3 | sylib | ⊢ ( 𝜑 → ∃ 𝑥 𝑥 ∈ 𝐴 ) |
| 5 | 4 2 | exlimddv | ⊢ ( 𝜑 → 𝜓 ) |