1stexg - Intuitionistic Logic Explorer

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Theorem 1stexg 6401

Description: Existence of the first member of a set. (Contributed by Jim Kingdon, 26-Jan-2019.)

**Assertion**
Ref	Expression
1stexg	⊢ (𝐴 ∈ 𝑉 → (1^st ‘𝐴) ∈ V)

**Proof of Theorem 1stexg**
Step	Hyp	Ref	Expression
1		elex 2833	. 2 ⊢ (𝐴 ∈ 𝑉 → 𝐴 ∈ V)
2		fo1st 6391	. . . 4 ⊢ 1^st :V–onto→V
3		fofn 5617	. . . 4 ⊢ (1^st :V–onto→V → 1^st Fn V)
4	2, 3	ax-mp 5	. . 3 ⊢ 1^st Fn V
5		funfvex 5712	. . . 4 ⊢ ((Fun 1^st ∧ 𝐴 ∈ dom 1^st ) → (1^st ‘𝐴) ∈ V)
6	5	funfni 5483	. . 3 ⊢ ((1^st Fn V ∧ 𝐴 ∈ V) → (1^st ‘𝐴) ∈ V)
7	4, 6	mpan 428	. 2 ⊢ (𝐴 ∈ V → (1^st ‘𝐴) ∈ V)
8	1, 7	syl 14	1 ⊢ (𝐴 ∈ 𝑉 → (1^st ‘𝐴) ∈ V)

Colors of variables: wff set class

This proof depends on syntax axioms: → wi 4 ∈ wcel 2209 Vcvv 2821 Fn wfn 5372 –onto→wfo 5375 ‘cfv 5377 1^st c1st 6372

This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-sep 4249 ax-pow 4311 ax-pr 4346 ax-un 4578

This proof depends on definitions: df-bi 117 df-3an 1011 df-tru 1405 df-nf 1514 df-sb 1816 df-eu 2089 df-mo 2090 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ral 2533 df-rex 2534 df-v 2823 df-sbc 3052 df-un 3224 df-in 3226 df-ss 3233 df-pw 3690 df-sn 3715 df-pr 3716 df-op 3718 df-uni 3936 df-br 4131 df-opab 4193 df-mpt 4194 df-id 4438 df-xp 4780 df-rel 4781 df-cnv 4782 df-co 4783 df-dm 4784 df-rn 4785 df-iota 5337 df-fun 5379 df-fn 5380 df-f 5381 df-fo 5383 df-fv 5385 df-1st 6374

This theorem is used by: elxp7 6404 xpopth 6410 eqop 6411 2nd1st 6414 2ndrn 6417 releldm2 6419 reldm 6420 dfoprab3 6425 elopabi 6431 mpofvex 6441 dfmpo 6459 cnvf1olem 6460 cnvoprab 6470 f1od2 6471 disjxp1 6472 elmpom 6474 xpmapenlem 7149 cnref1o 10051 fsumcnv 12204 fprodcnv 12392 qredeu 12875 qnumval 12963 xpsff1o 13670 txbas 15359 txdis 15378 vtxvalg 16257 vtxex 16259 wlkelvv 16590 wlk2f 16592