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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 3144 | . 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑)) | |
2 | 19.42v 1954 | . . . . 5 ⊢ (∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑)) | |
3 | 2 | bicomi 226 | . . . 4 ⊢ ((𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑)) |
4 | 3 | exbii 1848 | . . 3 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑)) |
5 | excom 2169 | . . . 4 ⊢ (∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
6 | df-rex 3144 | . . . . . 6 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
7 | 6 | bicomi 226 | . . . . 5 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑥 ∈ 𝐴 𝜑) |
8 | 7 | exbii 1848 | . . . 4 ⊢ (∃𝑦∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
9 | 5, 8 | bitri 277 | . . 3 ⊢ (∃𝑥∃𝑦(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
10 | 4, 9 | bitri 277 | . 2 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ ∃𝑦𝜑) ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
11 | 1, 10 | bitri 277 | 1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 208 ∧ wa 398 ∃wex 1780 ∈ wcel 2114 ∃wrex 3139 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-11 2161 |
This theorem depends on definitions: df-bi 209 df-an 399 df-ex 1781 df-rex 3144 |
This theorem is referenced by: 2ex2rexrot 3250 rexcom4a 3251 rexcom 3355 reuind 3744 uni0b 4864 iuncom4 4927 dfiun2g 4955 dfiun2gOLD 4956 iunn0 4989 iunxiun 5019 iinexg 5244 inuni 5246 iunopab 5446 xpiundi 5622 xpiundir 5623 cnvuni 5757 dmiun 5782 dmopab2rex 5786 elsnres 5892 rniun 6006 xpdifid 6025 imaco 6104 coiun 6109 abrexco 7003 imaiun 7004 fliftf 7068 fiun 7644 f1iun 7645 oprabrexex2 7679 releldm2 7742 oarec 8188 omeu 8211 eroveu 8392 dfac5lem2 9550 genpass 10431 supaddc 11608 supadd 11609 supmul1 11610 supmullem2 11612 supmul 11613 pceu 16183 4sqlem12 16292 mreiincl 16867 psgneu 18634 ntreq0 21685 unisngl 22135 metrest 23134 metuel2 23175 istrkg2ld 26246 fpwrelmapffslem 30468 omssubaddlem 31557 omssubadd 31558 bnj906 32202 satfdm 32616 dmopab3rexdif 32652 nosupno 33203 nosupfv 33206 bj-elsngl 34283 bj-restn0 34384 ismblfin 34948 itg2addnclem3 34960 sdclem1 35033 eldmqs1cossres 35908 prter2 36032 lshpsmreu 36260 islpln5 36686 islvol5 36730 cdlemftr3 37716 mapdpglem3 38826 hdmapglem7a 39078 diophrex 39392 imaiun1 40016 coiun1 40017 grumnudlem 40641 upbdrech 41592 |
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