Theorem fconstfvm 5924

Description: A constant function expressed in terms of its functionality, domain, and value. See also fconst2 5923. (Contributed by Jim Kingdon, 8-Jan-2019.)

Assertion

Ref	Expression
fconstfvm	|- ( E. y y e. A -> ( F : A --> { B } <-> ( F Fn A /\ A. x e. A ( F ` x ) = B ) ) )

Distinct variable groups:   x, A   x, B   x, F   y, A

Allowed substitution hints:   B( y)   F( y)

Proof of Theorem fconstfvm

Dummy variables w z are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ffn 5528	. . 3 |- ( F : A --> { B } -> F Fn A )
2		fvconst 5894	. . . 4 |- ( ( F : A --> { B } /\ x e. A ) -> ( F ` x ) = B )
3	2	ralrimiva 2623	. . 3 |- ( F : A --> { B } -> A. x e. A ( F ` x ) = B )
4	1, 3	jca 306	. 2 |- ( F : A --> { B } -> ( F Fn A /\ A. x e. A ( F ` x ) = B ) )
5		fvelrnb 5744	. . . . . . . . 9 |- ( F Fn A -> ( w e. ran F <-> E. z e. A ( F ` z ) = w ) )
6		fveq2 5690	. . . . . . . . . . . . . 14 |- ( x = z -> ( F ` x ) = ( F ` z ) )
7	6	eqeq1d 2247	. . . . . . . . . . . . 13 |- ( x = z -> ( ( F ` x ) = B <-> ( F ` z ) = B ) )
8	7	rspccva 2928	. . . . . . . . . . . 12 |- ( ( A. x e. A ( F ` x ) = B /\ z e. A ) -> ( F ` z ) = B )
9	8	eqeq1d 2247	. . . . . . . . . . 11 |- ( ( A. x e. A ( F ` x ) = B /\ z e. A ) -> ( ( F ` z ) = w <-> B = w ) )
10	9	rexbidva 2547	. . . . . . . . . 10 |- ( A. x e. A ( F ` x ) = B -> ( E. z e. A ( F ` z ) = w <-> E. z e. A B = w ) )
11		r19.9rmv 3616	. . . . . . . . . . 11 |- ( E. y y e. A -> ( B = w <-> E. z e. A B = w ) )
12	11	bicomd 141	. . . . . . . . . 10 |- ( E. y y e. A -> ( E. z e. A B = w <-> B = w ) )
13	10, 12	sylan9bbr 467	. . . . . . . . 9 |- ( ( E. y y e. A /\ A. x e. A ( F ` x ) = B ) -> ( E. z e. A ( F ` z ) = w <-> B = w ) )
14	5, 13	sylan9bbr 467	. . . . . . . 8 |- ( ( ( E. y y e. A /\ A. x e. A ( F ` x ) = B ) /\ F Fn A ) -> ( w e. ran F <-> B = w ) )
15		velsn 3722	. . . . . . . . 9 |- ( w e. { B } <-> w = B )
16		eqcom 2240	. . . . . . . . 9 |- ( w = B <-> B = w )
17	15, 16	bitr2i 185	. . . . . . . 8 |- ( B = w <-> w e. { B } )
18	14, 17	bitrdi 196	. . . . . . 7 |- ( ( ( E. y y e. A /\ A. x e. A ( F ` x ) = B ) /\ F Fn A ) -> ( w e. ran F <-> w e. { B } ) )
19	18	eqrdv 2236	. . . . . 6 |- ( ( ( E. y y e. A /\ A. x e. A ( F ` x ) = B ) /\ F Fn A ) -> ran F = { B } )
20	19	an32s 574	. . . . 5 |- ( ( ( E. y y e. A /\ F Fn A ) /\ A. x e. A ( F ` x ) = B ) -> ran F = { B } )
21	20	exp31 364	. . . 4 |- ( E. y y e. A -> ( F Fn A -> ( A. x e. A ( F ` x ) = B -> ran F = { B } ) ) )
22	21	imdistand 451	. . 3 |- ( E. y y e. A -> ( ( F Fn A /\ A. x e. A ( F ` x ) = B ) -> ( F Fn A /\ ran F = { B } ) ) )
23		df-fo 5378	. . . 4 |- ( F : A -onto-> { B } <-> ( F Fn A /\ ran F = { B } ) )
24		fof 5610	. . . 4 |- ( F : A -onto-> { B } -> F : A --> { B } )
25	23, 24	sylbir 135	. . 3 |- ( ( F Fn A /\ ran F = { B } ) -> F : A --> { B } )
26	22, 25	syl6 33	. 2 |- ( E. y y e. A -> ( ( F Fn A /\ A. x e. A ( F ` x ) = B ) -> F : A --> { B } ) )
27	4, 26	impbid2 143	1 |- ( E. y y e. A -> ( F : A --> { B } <-> ( F Fn A /\ A. x e. A ( F ` x ) = B ) ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1402   E.wex 1545   e. wcel 2209   A.wral 2528   E.wrex 2529   {csn 3705   ran crn 4770   Fn wfn 5367   -->wf 5368   -onto->wfo 5370   ` cfv 5372

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 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 4244  ax-pow 4306  ax-pr 4341

This theorem 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 3687  df-sn 3711  df-pr 3712  df-op 3714  df-uni 3931  df-br 4126  df-opab 4188  df-mpt 4189  df-id 4433  df-xp 4775  df-rel 4776  df-cnv 4777  df-co 4778  df-dm 4779  df-rn 4780  df-iota 5332  df-fun 5374  df-fn 5375  df-f 5376  df-fo 5378  df-fv 5380

This theorem is referenced by:  fconst3m  5925