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| Mirrors > Home > ILE Home > Th. List > Mathboxes > ralsmd | GIF version | ||
| Description: Deduction rule: Given "all some" applied to a class, the class is inhabited. This is stronger than ralsn0d 17045, which only concludes that the class is nonempty; see n0r 3535. (Contributed by David A. Wheeler, 20-Jul-2026.) |
| Ref | Expression |
|---|---|
| ralsmd.1 | ⊢ (𝜑 → ∀∃𝑥 ∈ 𝐴(𝜓 → 𝜒)) |
| Ref | Expression |
|---|---|
| ralsmd | ⊢ (𝜑 → ∃𝑥 𝑥 ∈ 𝐴) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ralsmd.1 | . . 3 ⊢ (𝜑 → ∀∃𝑥 ∈ 𝐴(𝜓 → 𝜒)) | |
| 2 | 1 | rals2d 17044 | . 2 ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 𝜓) |
| 3 | rexm 3627 | . 2 ⊢ (∃𝑥 ∈ 𝐴 𝜓 → ∃𝑥 𝑥 ∈ 𝐴) | |
| 4 | 2, 3 | syl 14 | 1 ⊢ (𝜑 → ∃𝑥 𝑥 ∈ 𝐴) |
| Colors of variables: wff set class |
| Syntax hints: → wi 4 ∃wex 1545 ∈ wcel 2209 ∃wrex 2529 ∀∃wrals 17035 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-5 1500 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-4 1563 ax-ial 1587 |
| This theorem depends on definitions: df-bi 117 df-rex 2534 df-rals 17037 |
| This theorem is referenced by: (None) |
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