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Mirrors > Home > MPE Home > Th. List > 0nelxp | Structured version Visualization version GIF version |
Description: The empty set is not a member of a Cartesian product. (Contributed by NM, 2-May-1996.) (Revised by Mario Carneiro, 26-Apr-2015.) (Proof shortened by JJ, 13-Aug-2021.) |
Ref | Expression |
---|---|
0nelxp | ⊢ ¬ ∅ ∈ (𝐴 × 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vex 3479 | . . . . . . 7 ⊢ 𝑥 ∈ V | |
2 | vex 3479 | . . . . . . 7 ⊢ 𝑦 ∈ V | |
3 | 1, 2 | opnzi 5475 | . . . . . 6 ⊢ ⟨𝑥, 𝑦⟩ ≠ ∅ |
4 | 3 | nesymi 2999 | . . . . 5 ⊢ ¬ ∅ = ⟨𝑥, 𝑦⟩ |
5 | 4 | intnanr 489 | . . . 4 ⊢ ¬ (∅ = ⟨𝑥, 𝑦⟩ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) |
6 | 5 | nex 1803 | . . 3 ⊢ ¬ ∃𝑦(∅ = ⟨𝑥, 𝑦⟩ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) |
7 | 6 | nex 1803 | . 2 ⊢ ¬ ∃𝑥∃𝑦(∅ = ⟨𝑥, 𝑦⟩ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) |
8 | elxp 5700 | . 2 ⊢ (∅ ∈ (𝐴 × 𝐵) ↔ ∃𝑥∃𝑦(∅ = ⟨𝑥, 𝑦⟩ ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵))) | |
9 | 7, 8 | mtbir 323 | 1 ⊢ ¬ ∅ ∈ (𝐴 × 𝐵) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ∧ wa 397 = wceq 1542 ∃wex 1782 ∈ wcel 2107 ∅c0 4323 ⟨cop 4635 × cxp 5675 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-ext 2704 ax-sep 5300 ax-nul 5307 ax-pr 5428 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-clel 2811 df-ne 2942 df-v 3477 df-dif 3952 df-un 3954 df-in 3956 df-ss 3966 df-nul 4324 df-if 4530 df-sn 4630 df-pr 4632 df-op 4636 df-opab 5212 df-xp 5683 |
This theorem is referenced by: 0nelrel0 5737 nrelv 5801 dmsn0 6209 onxpdisj 6491 mpoxopx0ov0 8201 dmtpos 8223 0nnq 10919 adderpq 10951 mulerpq 10952 lterpq 10965 0ncn 11128 structcnvcnv 17086 vtxval0 28299 iedgval0 28300 msrrcl 34534 |
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