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Mirrors > Home > MPE Home > Th. List > ceqsexv | Structured version Visualization version GIF version |
Description: Elimination of an existential quantifier, using implicit substitution. (Contributed by NM, 2-Mar-1995.) Avoid ax-12 2171. (Revised by Gino Giotto, 12-Oct-2024.) (Proof shortened by Wolf Lammen, 22-Jan-2025.) |
Ref | Expression |
---|---|
ceqsexv.1 | ⊢ 𝐴 ∈ V |
ceqsexv.2 | ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) |
Ref | Expression |
---|---|
ceqsexv | ⊢ (∃𝑥(𝑥 = 𝐴 ∧ 𝜑) ↔ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | alinexa 1845 | . . 3 ⊢ (∀𝑥(𝑥 = 𝐴 → ¬ 𝜑) ↔ ¬ ∃𝑥(𝑥 = 𝐴 ∧ 𝜑)) | |
2 | ceqsexv.1 | . . . 4 ⊢ 𝐴 ∈ V | |
3 | ceqsexv.2 | . . . . 5 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓)) | |
4 | 3 | notbid 317 | . . . 4 ⊢ (𝑥 = 𝐴 → (¬ 𝜑 ↔ ¬ 𝜓)) |
5 | 2, 4 | ceqsalv 3511 | . . 3 ⊢ (∀𝑥(𝑥 = 𝐴 → ¬ 𝜑) ↔ ¬ 𝜓) |
6 | 1, 5 | bitr3i 276 | . 2 ⊢ (¬ ∃𝑥(𝑥 = 𝐴 ∧ 𝜑) ↔ ¬ 𝜓) |
7 | 6 | con4bii 320 | 1 ⊢ (∃𝑥(𝑥 = 𝐴 ∧ 𝜑) ↔ 𝜓) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ wa 396 ∀wal 1539 = wceq 1541 ∃wex 1781 ∈ wcel 2106 Vcvv 3474 |
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 1913 ax-6 1971 ax-7 2011 ax-8 2108 |
This theorem depends on definitions: df-bi 206 df-an 397 df-ex 1782 df-clel 2810 |
This theorem is referenced by: ceqsexv2d 3528 ceqsex2v 3530 ceqsex3v 3531 gencbvex 3535 euxfr2w 3716 euxfr2 3718 inuni 5343 eqvinop 5487 elvvv 5751 dmfco 6987 fndmdif 7043 fndmin 7046 fmptco 7129 abrexco 7245 imaeqsexv 7362 imaeqexov 7647 uniuni 7751 elxp4 7915 elxp5 7916 brtpos2 8219 xpsnen 9057 xpcomco 9064 xpassen 9068 brttrcl2 9711 dfac5lem2 10121 cf0 10248 ltexprlem4 11036 pceu 16781 4sqlem12 16891 vdwapun 16909 gsumval3eu 19774 dprd2d2 19916 znleval 21116 metrest 24040 sleadd1 27482 addsuniflem 27494 addsasslem1 27496 addsasslem2 27497 mulsuniflem 27614 addsdilem1 27616 addsdilem2 27617 mulsasslem1 27628 mulsasslem2 27629 fmptcof2 31920 fpwrelmapffslem 31995 cusgredgex 34181 dfdm5 34813 dfrn5 34814 elima4 34816 brtxp 34921 brpprod 34926 elfix 34944 dfiota3 34964 brimg 34978 brapply 34979 brsuccf 34982 funpartlem 34983 brrestrict 34990 dfrecs2 34991 dfrdg4 34992 lshpsmreu 38065 isopos 38136 islpln5 38492 islvol5 38536 cdlemftr3 39522 dibelval3 40104 dicelval3 40137 mapdpglem3 40632 hdmapglem7a 40884 diophrex 41595 |
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