Theorem foelrni 5557

Description: A member of a surjective function's codomain is a value of the function. (Contributed by Thierry Arnoux, 23-Jan-2020.)

Assertion

Ref	Expression
foelrni	|- ( ( F : A -onto-> B /\ Y e. B ) -> E. x e. A ( F ` x ) = Y )

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

Proof of Theorem foelrni

Step	Hyp	Ref	Expression
1		forn 5430	. . . 4 |- ( F : A -onto-> B -> ran F = B )
2	1	eleq2d 2243	. . 3 |- ( F : A -onto-> B -> ( Y e. ran F <-> Y e. B ) )
3		fofn 5429	. . . 4 |- ( F : A -onto-> B -> F Fn A )
4		fvelrnb 5552	. . . 4 |- ( F Fn A -> ( Y e. ran F <-> E. x e. A ( F ` x ) = Y ) )
5	3, 4	syl 14	. . 3 |- ( F : A -onto-> B -> ( Y e. ran F <-> E. x e. A ( F ` x ) = Y ) )
6	2, 5	bitr3d 191	. 2 |- ( F : A -onto-> B -> ( Y e. B <-> E. x e. A ( F ` x ) = Y ) )
7	6	biimpa 296	1 |- ( ( F : A -onto-> B /\ Y e. B ) -> E. x e. A ( F ` x ) = Y )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1351   e. wcel 2144   E.wrex 2452   ran crn 4618   Fn wfn 5200   -onto->wfo 5203   ` cfv 5205

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 707  ax-5 1443  ax-7 1444  ax-gen 1445  ax-ie1 1489  ax-ie2 1490  ax-8 1500  ax-10 1501  ax-11 1502  ax-i12 1503  ax-bndl 1505  ax-4 1506  ax-17 1522  ax-i9 1526  ax-ial 1530  ax-i5r 1531  ax-14 2147  ax-ext 2155  ax-sep 4113  ax-pow 4166  ax-pr 4200

This theorem depends on definitions:  df-bi 117  df-3an 978  df-tru 1354  df-nf 1457  df-sb 1759  df-eu 2025  df-mo 2026  df-clab 2160  df-cleq 2166  df-clel 2169  df-nfc 2304  df-ral 2456  df-rex 2457  df-v 2735  df-sbc 2959  df-un 3128  df-in 3130  df-ss 3137  df-pw 3571  df-sn 3592  df-pr 3593  df-op 3595  df-uni 3803  df-br 3996  df-opab 4057  df-mpt 4058  df-id 4284  df-xp 4623  df-rel 4624  df-cnv 4625  df-co 4626  df-dm 4627  df-rn 4628  df-iota 5167  df-fun 5207  df-fn 5208  df-f 5209  df-fo 5211  df-fv 5213

This theorem is referenced by:  mhmid  12835  mhmmnd  12836  ghmgrp  12838