Theorem acfun 7350

Description: A convenient form of choice. The goal here is to state choice as the existence of a choice function on a set of inhabited sets, while making full use of our notation around functions and function values. (Contributed by Jim Kingdon, 20-Nov-2023.)

Hypotheses

Ref	Expression
acfun.ac	|- ( ph -> CHOICE )
acfun.a	|- ( ph -> A e. V )
acfun.m	|- ( ph -> A. x e. A E. w w e. x )

Assertion

Ref	Expression
acfun	|- ( ph -> E. f ( f Fn A /\ A. x e. A ( f ` x ) e. x ) )

Distinct variable groups:   A, f, x   ph, f, x   x, w

Allowed substitution hints:   ph( w)   A( w)   V( x, w, f)

Proof of Theorem acfun

Dummy variables u v y are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		acfun.a	. . . . 5 |- ( ph -> A e. V )
2	1	elexd 2790	. . . 4 |- ( ph -> A e. _V )
3		abid2 2328	. . . . . 6 |- { v | v e. u } = u
4		vex 2779	. . . . . 6 |- u e. _V
5	3, 4	eqeltri 2280	. . . . 5 |- { v | v e. u } e. _V
6	5	a1i 9	. . . 4 |- ( ( ph /\ u e. A ) -> { v | v e. u } e. _V )
7	2, 6	opabex3d 6229	. . 3 |- ( ph -> { <. u , v >. | ( u e. A /\ v e. u ) } e. _V )
8		acfun.ac	. . . 4 |- ( ph -> CHOICE )
9		df-ac 7349	. . . 4 |- (CHOICE <-> A. y E. f ( f C_ y /\ f Fn dom y ) )
10	8, 9	sylib 122	. . 3 |- ( ph -> A. y E. f ( f C_ y /\ f Fn dom y ) )
11		sseq2 3225	. . . . . 6 |- ( y = { <. u , v >. | ( u e. A /\ v e. u ) } -> ( f C_ y <-> f C_ { <. u , v >. | ( u e. A /\ v e. u ) } ) )
12		dmeq 4897	. . . . . . 7 |- ( y = { <. u , v >. | ( u e. A /\ v e. u ) } -> dom y = dom { <. u , v >. | ( u e. A /\ v e. u ) } )
13	12	fneq2d 5384	. . . . . 6 |- ( y = { <. u , v >. | ( u e. A /\ v e. u ) } -> ( f Fn dom y <-> f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) )
14	11, 13	anbi12d 473	. . . . 5 |- ( y = { <. u , v >. | ( u e. A /\ v e. u ) } -> ( ( f C_ y /\ f Fn dom y ) <-> ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) )
15	14	exbidv 1849	. . . 4 |- ( y = { <. u , v >. | ( u e. A /\ v e. u ) } -> ( E. f ( f C_ y /\ f Fn dom y ) <-> E. f ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) )
16	15	spcgv 2867	. . 3 |- ( { <. u , v >. | ( u e. A /\ v e. u ) } e. _V -> ( A. y E. f ( f C_ y /\ f Fn dom y ) -> E. f ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) )
17	7, 10, 16	sylc 62	. 2 |- ( ph -> E. f ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) )
18		simprr 531	. . . . . 6 |- ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) -> f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } )
19		acfun.m	. . . . . . . . . 10 |- ( ph -> A. x e. A E. w w e. x )
20		elequ2 2183	. . . . . . . . . . . . 13 |- ( x = u -> ( w e. x <-> w e. u ) )
21	20	exbidv 1849	. . . . . . . . . . . 12 |- ( x = u -> ( E. w w e. x <-> E. w w e. u ) )
22	21	cbvralv 2742	. . . . . . . . . . 11 |- ( A. x e. A E. w w e. x <-> A. u e. A E. w w e. u )
23		elequ1 2182	. . . . . . . . . . . . 13 |- ( w = v -> ( w e. u <-> v e. u ) )
24	23	cbvexv 1943	. . . . . . . . . . . 12 |- ( E. w w e. u <-> E. v v e. u )
25	24	ralbii 2514	. . . . . . . . . . 11 |- ( A. u e. A E. w w e. u <-> A. u e. A E. v v e. u )
26	22, 25	bitri 184	. . . . . . . . . 10 |- ( A. x e. A E. w w e. x <-> A. u e. A E. v v e. u )
27	19, 26	sylib 122	. . . . . . . . 9 |- ( ph -> A. u e. A E. v v e. u )
28		dmopab3 4910	. . . . . . . . 9 |- ( A. u e. A E. v v e. u <-> dom { <. u , v >. | ( u e. A /\ v e. u ) } = A )
29	27, 28	sylib 122	. . . . . . . 8 |- ( ph -> dom { <. u , v >. | ( u e. A /\ v e. u ) } = A )
30	29	fneq2d 5384	. . . . . . 7 |- ( ph -> ( f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } <-> f Fn A ) )
31	30	adantr 276	. . . . . 6 |- ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) -> ( f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } <-> f Fn A ) )
32	18, 31	mpbid 147	. . . . 5 |- ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) -> f Fn A )
33		simplrl 535	. . . . . . . . 9 |- ( ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) /\ x e. A ) -> f C_ { <. u , v >. | ( u e. A /\ v e. u ) } )
34		fnopfv 5733	. . . . . . . . . 10 |- ( ( f Fn A /\ x e. A ) -> <. x , ( f ` x ) >. e. f )
35	32, 34	sylan 283	. . . . . . . . 9 |- ( ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) /\ x e. A ) -> <. x , ( f ` x ) >. e. f )
36	33, 35	sseldd 3202	. . . . . . . 8 |- ( ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) /\ x e. A ) -> <. x , ( f ` x ) >. e. { <. u , v >. | ( u e. A /\ v e. u ) } )
37		vex 2779	. . . . . . . . 9 |- x e. _V
38		vex 2779	. . . . . . . . . 10 |- f e. _V
39	38, 37	fvex 5619	. . . . . . . . 9 |- ( f ` x ) e. _V
40		eleq1 2270	. . . . . . . . . 10 |- ( u = x -> ( u e. A <-> x e. A ) )
41		elequ2 2183	. . . . . . . . . 10 |- ( u = x -> ( v e. u <-> v e. x ) )
42	40, 41	anbi12d 473	. . . . . . . . 9 |- ( u = x -> ( ( u e. A /\ v e. u ) <-> ( x e. A /\ v e. x ) ) )
43		eleq1 2270	. . . . . . . . . 10 |- ( v = ( f ` x ) -> ( v e. x <-> ( f ` x ) e. x ) )
44	43	anbi2d 464	. . . . . . . . 9 |- ( v = ( f ` x ) -> ( ( x e. A /\ v e. x ) <-> ( x e. A /\ ( f ` x ) e. x ) ) )
45	37, 39, 42, 44	opelopab 4336	. . . . . . . 8 |- ( <. x , ( f ` x ) >. e. { <. u , v >. | ( u e. A /\ v e. u ) } <-> ( x e. A /\ ( f ` x ) e. x ) )
46	36, 45	sylib 122	. . . . . . 7 |- ( ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) /\ x e. A ) -> ( x e. A /\ ( f ` x ) e. x ) )
47	46	simprd 114	. . . . . 6 |- ( ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) /\ x e. A ) -> ( f ` x ) e. x )
48	47	ralrimiva 2581	. . . . 5 |- ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) -> A. x e. A ( f ` x ) e. x )
49	32, 48	jca 306	. . . 4 |- ( ( ph /\ ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) ) -> ( f Fn A /\ A. x e. A ( f ` x ) e. x ) )
50	49	ex 115	. . 3 |- ( ph -> ( ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) -> ( f Fn A /\ A. x e. A ( f ` x ) e. x ) ) )
51	50	eximdv 1904	. 2 |- ( ph -> ( E. f ( f C_ { <. u , v >. | ( u e. A /\ v e. u ) } /\ f Fn dom { <. u , v >. | ( u e. A /\ v e. u ) } ) -> E. f ( f Fn A /\ A. x e. A ( f ` x ) e. x ) ) )
52	17, 51	mpd 13	1 |- ( ph -> E. f ( f Fn A /\ A. x e. A ( f ` x ) e. x ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   A.wal 1371   = wceq 1373   E.wex 1516   e. wcel 2178   {cab 2193   A.wral 2486   _Vcvv 2776   C_ wss 3174   <.cop 3646   {copab 4120   dom cdm 4693   Fn wfn 5285   ` cfv 5290  CHOICEwac 7348

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-13 2180  ax-14 2181  ax-ext 2189  ax-coll 4175  ax-sep 4178  ax-pow 4234  ax-pr 4269  ax-un 4498

This theorem depends on definitions:  df-bi 117  df-3an 983  df-tru 1376  df-nf 1485  df-sb 1787  df-eu 2058  df-mo 2059  df-clab 2194  df-cleq 2200  df-clel 2203  df-nfc 2339  df-ral 2491  df-rex 2492  df-reu 2493  df-rab 2495  df-v 2778  df-sbc 3006  df-csb 3102  df-un 3178  df-in 3180  df-ss 3187  df-pw 3628  df-sn 3649  df-pr 3650  df-op 3652  df-uni 3865  df-iun 3943  df-br 4060  df-opab 4122  df-mpt 4123  df-id 4358  df-xp 4699  df-rel 4700  df-cnv 4701  df-co 4702  df-dm 4703  df-rn 4704  df-res 4705  df-ima 4706  df-iota 5251  df-fun 5292  df-fn 5293  df-f 5294  df-f1 5295  df-fo 5296  df-f1o 5297  df-fv 5298  df-ac 7349

This theorem is referenced by:  exmidaclem  7351