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Mirrors > Home > ILE Home > Th. List > rexcom4 | GIF version |
Description: Commutation of restricted and unrestricted existential quantifiers. (Contributed by NM, 12-Apr-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.) |
Ref | Expression |
---|---|
rexcom4 | ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rexcom 2593 | . 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ V 𝜑 ↔ ∃𝑦 ∈ V ∃𝑥 ∈ 𝐴 𝜑) | |
2 | rexv 2699 | . . 3 ⊢ (∃𝑦 ∈ V 𝜑 ↔ ∃𝑦𝜑) | |
3 | 2 | rexbii 2440 | . 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ V 𝜑 ↔ ∃𝑥 ∈ 𝐴 ∃𝑦𝜑) |
4 | rexv 2699 | . 2 ⊢ (∃𝑦 ∈ V ∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) | |
5 | 1, 3, 4 | 3bitr3i 209 | 1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 104 ∃wex 1468 ∃wrex 2415 Vcvv 2681 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2119 |
This theorem depends on definitions: df-bi 116 df-tru 1334 df-nf 1437 df-sb 1736 df-clab 2124 df-cleq 2130 df-clel 2133 df-nfc 2268 df-rex 2420 df-v 2683 |
This theorem is referenced by: rexcom4a 2705 reuind 2884 iuncom4 3815 dfiun2g 3840 iunn0m 3868 iunxiun 3889 iinexgm 4074 inuni 4075 iunopab 4198 xpiundi 4592 xpiundir 4593 cnvuni 4720 dmiun 4743 elres 4850 elsnres 4851 rniun 4944 imaco 5039 coiun 5043 fun11iun 5381 abrexco 5653 imaiun 5654 fliftf 5693 rexrnmpo 5879 oprabrexex2 6021 releldm2 6076 eroveu 6513 genpassl 7325 genpassu 7326 ltexprlemopl 7402 ltexprlemopu 7404 ntreq0 12290 metrest 12664 |
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