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Mirrors > Home > MPE Home > Th. List > rexcom4 | Structured version Visualization version GIF version |
Description: Commutation of restricted and unrestricted existential quantifiers. (Contributed by NM, 12-Apr-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.) Reduce axiom dependencies. (Revised by BJ, 13-Jun-2019.) |
Ref | Expression |
---|---|
rexcom4 | ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-rex 3112 | . 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑)) | |
2 | 19.42v 1954 | . . . . 5 ⊢ (∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑)) | |
3 | 2 | bicomi 227 | . . . 4 ⊢ ((𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑)) |
4 | 3 | exbii 1849 | . . 3 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑)) |
5 | excom 2166 | . . . 4 ⊢ (∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
6 | df-rex 3112 | . . . . . 6 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
7 | 6 | bicomi 227 | . . . . 5 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑥 ∈ 𝐴 𝜑) |
8 | 7 | exbii 1849 | . . . 4 ⊢ (∃𝑦∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
9 | 5, 8 | bitri 278 | . . 3 ⊢ (∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
10 | 4, 9 | bitri 278 | . 2 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
11 | 1, 10 | bitri 278 | 1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 209 ∧ wa 399 ∃wex 1781 ∈ wcel 2111 ∃wrex 3107 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-11 2158 |
This theorem depends on definitions: df-bi 210 df-an 400 df-ex 1782 df-rex 3112 |
This theorem is referenced by: 2ex2rexrot 3213 rexcom4a 3214 rexcom 3308 reuind 3692 uni0b 4826 iuncom4 4889 dfiun2g 4917 dfiun2gOLD 4918 iunn0 4952 iunxiun 4982 iinexg 5208 inuni 5210 iunopab 5411 xpiundi 5586 xpiundir 5587 cnvuni 5721 dmiun 5746 dmopab2rex 5750 elsnres 5858 rniun 5973 xpdifid 5992 imaco 6071 coiun 6076 abrexco 6981 imaiun 6982 fliftf 7047 fiun 7626 f1iun 7627 oprabrexex2 7661 releldm2 7724 oarec 8171 omeu 8194 eroveu 8375 dfac5lem2 9535 genpass 10420 supaddc 11595 supadd 11596 supmul1 11597 supmullem2 11599 supmul 11600 pceu 16173 4sqlem12 16282 mreiincl 16859 psgneu 18626 ntreq0 21682 unisngl 22132 metrest 23131 metuel2 23172 istrkg2ld 26254 fpwrelmapffslem 30494 omssubaddlem 31667 omssubadd 31668 bnj906 32312 satfdm 32729 dmopab3rexdif 32765 nosupno 33316 nosupfv 33319 bj-elsngl 34404 bj-restn0 34505 ismblfin 35098 itg2addnclem3 35110 sdclem1 35181 eldmqs1cossres 36053 prter2 36177 lshpsmreu 36405 islpln5 36831 islvol5 36875 cdlemftr3 37861 mapdpglem3 38971 hdmapglem7a 39223 diophrex 39716 imaiun1 40352 coiun1 40353 grumnudlem 40993 upbdrech 41937 |
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