Theorem subg0 13738

Description: A subgroup of a group must have the same identity as the group. (Contributed by Stefan O'Rear, 27-Nov-2014.) (Revised by Mario Carneiro, 30-Apr-2015.)

Hypotheses

Ref	Expression
subg0.h	⊢ 𝐻 = (𝐺 ↾s 𝑆)
subg0.i	⊢ 0 = (0g‘𝐺)

Assertion

Ref	Expression
subg0	⊢ (𝑆 ∈ (SubGrp‘𝐺) → 0 = (0g‘𝐻))

Proof of Theorem subg0

Step	Hyp	Ref	Expression
1		subg0.h	. . . . . 6 ⊢ 𝐻 = (𝐺 ↾s 𝑆)
2	1	a1i 9	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝐻 = (𝐺 ↾s 𝑆))
3		eqid 2229	. . . . . 6 ⊢ (+g‘𝐺) = (+g‘𝐺)
4	3	a1i 9	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (+g‘𝐺) = (+g‘𝐺))
5		id 19	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝑆 ∈ (SubGrp‘𝐺))
6		subgrcl 13737	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝐺 ∈ Grp)
7	2, 4, 5, 6	ressplusgd 13183	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (+g‘𝐺) = (+g‘𝐻))
8	7	oveqd 6027	. . 3 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → ((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = ((0g‘𝐻)(+g‘𝐻)(0g‘𝐻)))
9	1	subggrp 13735	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝐻 ∈ Grp)
10		eqid 2229	. . . . . 6 ⊢ (Base‘𝐻) = (Base‘𝐻)
11		eqid 2229	. . . . . 6 ⊢ (0g‘𝐻) = (0g‘𝐻)
12	10, 11	grpidcl 13583	. . . . 5 ⊢ (𝐻 ∈ Grp → (0g‘𝐻) ∈ (Base‘𝐻))
13	9, 12	syl 14	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ (Base‘𝐻))
14		eqid 2229	. . . . 5 ⊢ (+g‘𝐻) = (+g‘𝐻)
15	10, 14, 11	grplid 13585	. . . 4 ⊢ ((𝐻 ∈ Grp ∧ (0g‘𝐻) ∈ (Base‘𝐻)) → ((0g‘𝐻)(+g‘𝐻)(0g‘𝐻)) = (0g‘𝐻))
16	9, 13, 15	syl2anc 411	. . 3 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → ((0g‘𝐻)(+g‘𝐻)(0g‘𝐻)) = (0g‘𝐻))
17	8, 16	eqtrd 2262	. 2 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → ((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = (0g‘𝐻))
18		eqid 2229	. . . . 5 ⊢ (Base‘𝐺) = (Base‘𝐺)
19	18	subgss 13732	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝑆 ⊆ (Base‘𝐺))
20	1	subgbas 13736	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝑆 = (Base‘𝐻))
21	13, 20	eleqtrrd 2309	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ 𝑆)
22	19, 21	sseldd 3225	. . 3 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ (Base‘𝐺))
23		subg0.i	. . . 4 ⊢ 0 = (0g‘𝐺)
24	18, 3, 23	grpid 13593	. . 3 ⊢ ((𝐺 ∈ Grp ∧ (0g‘𝐻) ∈ (Base‘𝐺)) → (((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = (0g‘𝐻) ↔ 0 = (0g‘𝐻)))
25	6, 22, 24	syl2anc 411	. 2 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = (0g‘𝐻) ↔ 0 = (0g‘𝐻)))
26	17, 25	mpbid 147	1 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 0 = (0g‘𝐻))

Syntax hints:   → wi 4   ↔ wb 105   = wceq 1395   ∈ wcel 2200  ‘cfv 5321  (class class class)co 6010  Basecbs 13053   ↾_s cress 13054  +_gcplusg 13131  0_gc0g 13310  Grpcgrp 13554  SubGrpcsubg 13725

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-in1 617  ax-in2 618  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-13 2202  ax-14 2203  ax-ext 2211  ax-sep 4202  ax-pow 4259  ax-pr 4294  ax-un 4525  ax-setind 4630  ax-cnex 8106  ax-resscn 8107  ax-1cn 8108  ax-1re 8109  ax-icn 8110  ax-addcl 8111  ax-addrcl 8112  ax-mulcl 8113  ax-addcom 8115  ax-addass 8117  ax-i2m1 8120  ax-0lt1 8121  ax-0id 8123  ax-rnegex 8124  ax-pre-ltirr 8127  ax-pre-ltadd 8131

This theorem depends on definitions:  df-bi 117  df-3an 1004  df-tru 1398  df-fal 1401  df-nf 1507  df-sb 1809  df-eu 2080  df-mo 2081  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ne 2401  df-nel 2496  df-ral 2513  df-rex 2514  df-reu 2515  df-rmo 2516  df-rab 2517  df-v 2801  df-sbc 3029  df-csb 3125  df-dif 3199  df-un 3201  df-in 3203  df-ss 3210  df-nul 3492  df-pw 3651  df-sn 3672  df-pr 3673  df-op 3675  df-uni 3889  df-int 3924  df-br 4084  df-opab 4146  df-mpt 4147  df-id 4385  df-xp 4726  df-rel 4727  df-cnv 4728  df-co 4729  df-dm 4730  df-rn 4731  df-res 4732  df-ima 4733  df-iota 5281  df-fun 5323  df-fn 5324  df-fv 5329  df-riota 5963  df-ov 6013  df-oprab 6014  df-mpo 6015  df-pnf 8199  df-mnf 8200  df-ltxr 8202  df-inn 9127  df-2 9185  df-ndx 13056  df-slot 13057  df-base 13059  df-sets 13060  df-iress 13061  df-plusg 13144  df-0g 13312  df-mgm 13410  df-sgrp 13456  df-mnd 13471  df-grp 13557  df-subg 13728

This theorem is referenced by:  subginv  13739  subg0cl  13740  subgmulg  13746  subrng0  14192  subrg0  14213  mpl0fi  14687