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Mirrors > Home > ILE Home > Th. List > 1stexg | GIF version |
Description: Existence of the first member of a set. (Contributed by Jim Kingdon, 26-Jan-2019.) |
Ref | Expression |
---|---|
1stexg | ⊢ (𝐴 ∈ 𝑉 → (1st ‘𝐴) ∈ V) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elex 2700 | . 2 ⊢ (𝐴 ∈ 𝑉 → 𝐴 ∈ V) | |
2 | fo1st 6063 | . . . 4 ⊢ 1st :V–onto→V | |
3 | fofn 5355 | . . . 4 ⊢ (1st :V–onto→V → 1st Fn V) | |
4 | 2, 3 | ax-mp 5 | . . 3 ⊢ 1st Fn V |
5 | funfvex 5446 | . . . 4 ⊢ ((Fun 1st ∧ 𝐴 ∈ dom 1st ) → (1st ‘𝐴) ∈ V) | |
6 | 5 | funfni 5231 | . . 3 ⊢ ((1st Fn V ∧ 𝐴 ∈ V) → (1st ‘𝐴) ∈ V) |
7 | 4, 6 | mpan 421 | . 2 ⊢ (𝐴 ∈ V → (1st ‘𝐴) ∈ V) |
8 | 1, 7 | syl 14 | 1 ⊢ (𝐴 ∈ 𝑉 → (1st ‘𝐴) ∈ V) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∈ wcel 1481 Vcvv 2689 Fn wfn 5126 –onto→wfo 5129 ‘cfv 5131 1st c1st 6044 |
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 699 ax-5 1424 ax-7 1425 ax-gen 1426 ax-ie1 1470 ax-ie2 1471 ax-8 1483 ax-10 1484 ax-11 1485 ax-i12 1486 ax-bndl 1487 ax-4 1488 ax-13 1492 ax-14 1493 ax-17 1507 ax-i9 1511 ax-ial 1515 ax-i5r 1516 ax-ext 2122 ax-sep 4054 ax-pow 4106 ax-pr 4139 ax-un 4363 |
This theorem depends on definitions: df-bi 116 df-3an 965 df-tru 1335 df-nf 1438 df-sb 1737 df-eu 2003 df-mo 2004 df-clab 2127 df-cleq 2133 df-clel 2136 df-nfc 2271 df-ral 2422 df-rex 2423 df-v 2691 df-sbc 2914 df-un 3080 df-in 3082 df-ss 3089 df-pw 3517 df-sn 3538 df-pr 3539 df-op 3541 df-uni 3745 df-br 3938 df-opab 3998 df-mpt 3999 df-id 4223 df-xp 4553 df-rel 4554 df-cnv 4555 df-co 4556 df-dm 4557 df-rn 4558 df-iota 5096 df-fun 5133 df-fn 5134 df-f 5135 df-fo 5137 df-fv 5139 df-1st 6046 |
This theorem is referenced by: elxp7 6076 xpopth 6082 eqop 6083 2nd1st 6086 2ndrn 6089 releldm2 6091 reldm 6092 dfoprab3 6097 elopabi 6101 mpofvex 6109 dfmpo 6128 cnvf1olem 6129 cnvoprab 6139 f1od2 6140 disjxp1 6141 xpmapenlem 6751 cnref1o 9469 fsumcnv 11238 qredeu 11814 qnumval 11899 txbas 12466 txdis 12485 |
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