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Mirrors > Home > MPE Home > Th. List > Mathboxes > falseral0 | Structured version Visualization version GIF version |
Description: A false statement can only be true for elements of an empty set. (Contributed by AV, 30-Oct-2020.) |
Ref | Expression |
---|---|
falseral0 | ⊢ ((∀𝑥 ¬ 𝜑 ∧ ∀𝑥 ∈ 𝐴 𝜑) → 𝐴 = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-ral 2901 | . 2 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) | |
2 | 19.26 1786 | . . 3 ⊢ (∀𝑥(¬ 𝜑 ∧ (𝑥 ∈ 𝐴 → 𝜑)) ↔ (∀𝑥 ¬ 𝜑 ∧ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑))) | |
3 | con3 148 | . . . . . . 7 ⊢ ((𝑥 ∈ 𝐴 → 𝜑) → (¬ 𝜑 → ¬ 𝑥 ∈ 𝐴)) | |
4 | 3 | impcom 445 | . . . . . 6 ⊢ ((¬ 𝜑 ∧ (𝑥 ∈ 𝐴 → 𝜑)) → ¬ 𝑥 ∈ 𝐴) |
5 | 4 | alimi 1730 | . . . . 5 ⊢ (∀𝑥(¬ 𝜑 ∧ (𝑥 ∈ 𝐴 → 𝜑)) → ∀𝑥 ¬ 𝑥 ∈ 𝐴) |
6 | alnex 1697 | . . . . 5 ⊢ (∀𝑥 ¬ 𝑥 ∈ 𝐴 ↔ ¬ ∃𝑥 𝑥 ∈ 𝐴) | |
7 | 5, 6 | sylib 207 | . . . 4 ⊢ (∀𝑥(¬ 𝜑 ∧ (𝑥 ∈ 𝐴 → 𝜑)) → ¬ ∃𝑥 𝑥 ∈ 𝐴) |
8 | notnotb 303 | . . . . 5 ⊢ (𝐴 = ∅ ↔ ¬ ¬ 𝐴 = ∅) | |
9 | neq0 3889 | . . . . 5 ⊢ (¬ 𝐴 = ∅ ↔ ∃𝑥 𝑥 ∈ 𝐴) | |
10 | 8, 9 | xchbinx 323 | . . . 4 ⊢ (𝐴 = ∅ ↔ ¬ ∃𝑥 𝑥 ∈ 𝐴) |
11 | 7, 10 | sylibr 223 | . . 3 ⊢ (∀𝑥(¬ 𝜑 ∧ (𝑥 ∈ 𝐴 → 𝜑)) → 𝐴 = ∅) |
12 | 2, 11 | sylbir 224 | . 2 ⊢ ((∀𝑥 ¬ 𝜑 ∧ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) → 𝐴 = ∅) |
13 | 1, 12 | sylan2b 491 | 1 ⊢ ((∀𝑥 ¬ 𝜑 ∧ ∀𝑥 ∈ 𝐴 𝜑) → 𝐴 = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 383 ∀wal 1473 = wceq 1475 ∃wex 1695 ∈ wcel 1977 ∀wral 2896 ∅c0 3874 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ral 2901 df-v 3175 df-dif 3543 df-nul 3875 |
This theorem is referenced by: uvtxa01vtx0 40623 |
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