Theorem ghmgrp 17539

Description: The image of a group G under a group homomorphism F is a group. This is a stronger result than that usually found in the literature, since the target of the homomorphism (operator O in our model) need not have any of the properties of a group as a prerequisite. (Contributed by Paul Chapman, 25-Apr-2008.) (Revised by Mario Carneiro, 12-May-2014.) (Revised by Thierry Arnoux, 25-Jan-2020.)

Hypotheses

Ref	Expression
ghmgrp.f	|- ( ( ph /\ x e. X /\ y e. X ) -> ( F ` ( x .+ y ) ) = ( ( F ` x ) .+^ ( F ` y ) ) )
ghmgrp.x	|- X = ( Base ` G )
ghmgrp.y	|- Y = ( Base ` H )
ghmgrp.p	|- .+ = ( +g ` G )
ghmgrp.q	|- .+^ = ( +g ` H )
ghmgrp.1	|- ( ph -> F : X -onto-> Y )
ghmgrp.3	|- ( ph -> G e. Grp )

Assertion

Ref	Expression
ghmgrp	|- ( ph -> H e. Grp )

Distinct variable groups:   x, F, y   x, G, y   x, .+ , y   x, H, y   x, X, y   x, Y, y   x, .+^ , y   ph, x, y

Proof of Theorem ghmgrp

Dummy variables a f i are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ghmgrp.f	. . 3 |- ( ( ph /\ x e. X /\ y e. X ) -> ( F ` ( x .+ y ) ) = ( ( F ` x ) .+^ ( F ` y ) ) )
2		ghmgrp.x	. . 3 |- X = ( Base ` G )
3		ghmgrp.y	. . 3 |- Y = ( Base ` H )
4		ghmgrp.p	. . 3 |- .+ = ( +g ` G )
5		ghmgrp.q	. . 3 |- .+^ = ( +g ` H )
6		ghmgrp.1	. . 3 |- ( ph -> F : X -onto-> Y )
7		ghmgrp.3	. . . 4 |- ( ph -> G e. Grp )
8		grpmnd 17429	. . . 4 |- ( G e. Grp -> G e. Mnd )
9	7, 8	syl 17	. . 3 |- ( ph -> G e. Mnd )
10	1, 2, 3, 4, 5, 6, 9	mhmmnd 17537	. 2 |- ( ph -> H e. Mnd )
11		fof 6115	. . . . . . . 8 |- ( F : X -onto-> Y -> F : X --> Y )
12	6, 11	syl 17	. . . . . . 7 |- ( ph -> F : X --> Y )
13	12	ad3antrrr 766	. . . . . 6 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> F : X --> Y )
14	7	ad3antrrr 766	. . . . . . 7 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> G e. Grp )
15		simplr 792	. . . . . . 7 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> i e. X )
16		eqid 2622	. . . . . . . 8 |- ( invg ` G ) = ( invg ` G )
17	2, 16	grpinvcl 17467	. . . . . . 7 |- ( ( G e. Grp /\ i e. X ) -> ( ( invg ` G ) ` i ) e. X )
18	14, 15, 17	syl2anc 693	. . . . . 6 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( ( invg ` G ) ` i ) e. X )
19	13, 18	ffvelrnd 6360	. . . . 5 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` ( ( invg ` G ) ` i ) ) e. Y )
20	1	3adant1r 1319	. . . . . . . . 9 |- ( ( ( ph /\ i e. X ) /\ x e. X /\ y e. X ) -> ( F ` ( x .+ y ) ) = ( ( F ` x ) .+^ ( F ` y ) ) )
21	7, 17	sylan 488	. . . . . . . . 9 |- ( ( ph /\ i e. X ) -> ( ( invg ` G ) ` i ) e. X )
22		simpr 477	. . . . . . . . 9 |- ( ( ph /\ i e. X ) -> i e. X )
23	20, 21, 22	mhmlem 17535	. . . . . . . 8 |- ( ( ph /\ i e. X ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( ( F ` ( ( invg ` G ) ` i ) ) .+^ ( F ` i ) ) )
24	23	adantlr 751	. . . . . . 7 |- ( ( ( ph /\ a e. Y ) /\ i e. X ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( ( F ` ( ( invg ` G ) ` i ) ) .+^ ( F ` i ) ) )
25	24	adantr 481	. . . . . 6 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( ( F ` ( ( invg ` G ) ` i ) ) .+^ ( F ` i ) ) )
26		eqid 2622	. . . . . . . . . 10 |- ( 0g ` G ) = ( 0g ` G )
27	2, 4, 26, 16	grplinv 17468	. . . . . . . . 9 |- ( ( G e. Grp /\ i e. X ) -> ( ( ( invg ` G ) ` i ) .+ i ) = ( 0g ` G ) )
28	27	fveq2d 6195	. . . . . . . 8 |- ( ( G e. Grp /\ i e. X ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( F ` ( 0g ` G ) ) )
29	14, 15, 28	syl2anc 693	. . . . . . 7 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( F ` ( 0g ` G ) ) )
30	1, 2, 3, 4, 5, 6, 9, 26	mhmid 17536	. . . . . . . 8 |- ( ph -> ( F ` ( 0g ` G ) ) = ( 0g ` H ) )
31	30	ad3antrrr 766	. . . . . . 7 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` ( 0g ` G ) ) = ( 0g ` H ) )
32	29, 31	eqtrd 2656	. . . . . 6 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` ( ( ( invg ` G ) ` i ) .+ i ) ) = ( 0g ` H ) )
33		simpr 477	. . . . . . 7 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( F ` i ) = a )
34	33	oveq2d 6666	. . . . . 6 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( ( F ` ( ( invg ` G ) ` i ) ) .+^ ( F ` i ) ) = ( ( F ` ( ( invg ` G ) ` i ) ) .+^ a ) )
35	25, 32, 34	3eqtr3rd 2665	. . . . 5 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> ( ( F ` ( ( invg ` G ) ` i ) ) .+^ a ) = ( 0g ` H ) )
36		oveq1 6657	. . . . . . 7 |- ( f = ( F ` ( ( invg ` G ) ` i ) ) -> ( f .+^ a ) = ( ( F ` ( ( invg ` G ) ` i ) ) .+^ a ) )
37	36	eqeq1d 2624	. . . . . 6 |- ( f = ( F ` ( ( invg ` G ) ` i ) ) -> ( ( f .+^ a ) = ( 0g ` H ) <-> ( ( F ` ( ( invg ` G ) ` i ) ) .+^ a ) = ( 0g ` H ) ) )
38	37	rspcev 3309	. . . . 5 |- ( ( ( F ` ( ( invg ` G ) ` i ) ) e. Y /\ ( ( F ` ( ( invg ` G ) ` i ) ) .+^ a ) = ( 0g ` H ) ) -> E. f e. Y ( f .+^ a ) = ( 0g ` H ) )
39	19, 35, 38	syl2anc 693	. . . 4 |- ( ( ( ( ph /\ a e. Y ) /\ i e. X ) /\ ( F ` i ) = a ) -> E. f e. Y ( f .+^ a ) = ( 0g ` H ) )
40		foelrni 6244	. . . . 5 |- ( ( F : X -onto-> Y /\ a e. Y ) -> E. i e. X ( F ` i ) = a )
41	6, 40	sylan 488	. . . 4 |- ( ( ph /\ a e. Y ) -> E. i e. X ( F ` i ) = a )
42	39, 41	r19.29a 3078	. . 3 |- ( ( ph /\ a e. Y ) -> E. f e. Y ( f .+^ a ) = ( 0g ` H ) )
43	42	ralrimiva 2966	. 2 |- ( ph -> A. a e. Y E. f e. Y ( f .+^ a ) = ( 0g ` H ) )
44		eqid 2622	. . 3 |- ( 0g ` H ) = ( 0g ` H )
45	3, 5, 44	isgrp 17428	. 2 |- ( H e. Grp <-> ( H e. Mnd /\ A. a e. Y E. f e. Y ( f .+^ a ) = ( 0g ` H ) ) )
46	10, 43, 45	sylanbrc 698	1 |- ( ph -> H e. Grp )

Syntax hints:   -> wi 4   /\ wa 384   /\ w3a 1037   = wceq 1483   e. wcel 1990   A.wral 2912   E.wrex 2913   -->wf 5884   -onto->wfo 5886   ` cfv 5888  (class class class)co 6650   Basecbs 15857   +g cplusg 15941   0gc0g 16100   Mndcmnd 17294   Grpcgrp 17422   invgcminusg 17423

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-ral 2917  df-rex 2918  df-reu 2919  df-rmo 2920  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-riota 6611  df-ov 6653  df-0g 16102  df-mgm 17242  df-sgrp 17284  df-mnd 17295  df-grp 17425  df-minusg 17426

This theorem is referenced by:  ghmfghm  18236  ghmabl  18238