Theorem subg0 13683

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 2209	. . . . . 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 13682	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝐺 ∈ Grp)
7	2, 4, 5, 6	ressplusgd 13128	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (+g‘𝐺) = (+g‘𝐻))
8	7	oveqd 5991	. . 3 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → ((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = ((0g‘𝐻)(+g‘𝐻)(0g‘𝐻)))
9	1	subggrp 13680	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝐻 ∈ Grp)
10		eqid 2209	. . . . . 6 ⊢ (Base‘𝐻) = (Base‘𝐻)
11		eqid 2209	. . . . . 6 ⊢ (0g‘𝐻) = (0g‘𝐻)
12	10, 11	grpidcl 13528	. . . . 5 ⊢ (𝐻 ∈ Grp → (0g‘𝐻) ∈ (Base‘𝐻))
13	9, 12	syl 14	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ (Base‘𝐻))
14		eqid 2209	. . . . 5 ⊢ (+g‘𝐻) = (+g‘𝐻)
15	10, 14, 11	grplid 13530	. . . 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 2242	. 2 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → ((0g‘𝐻)(+g‘𝐺)(0g‘𝐻)) = (0g‘𝐻))
18		eqid 2209	. . . . 5 ⊢ (Base‘𝐺) = (Base‘𝐺)
19	18	subgss 13677	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝑆 ⊆ (Base‘𝐺))
20	1	subgbas 13681	. . . . 5 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → 𝑆 = (Base‘𝐻))
21	13, 20	eleqtrrd 2289	. . . 4 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ 𝑆)
22	19, 21	sseldd 3205	. . 3 ⊢ (𝑆 ∈ (SubGrp‘𝐺) → (0g‘𝐻) ∈ (Base‘𝐺))
23		subg0.i	. . . 4 ⊢ 0 = (0g‘𝐺)
24	18, 3, 23	grpid 13538	. . 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 1375   ∈ wcel 2180  ‘cfv 5294  (class class class)co 5974  Basecbs 12998   ↾_s cress 12999  +_gcplusg 13076  0_gc0g 13255  Grpcgrp 13499  SubGrpcsubg 13670

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 713  ax-5 1473  ax-7 1474  ax-gen 1475  ax-ie1 1519  ax-ie2 1520  ax-8 1530  ax-10 1531  ax-11 1532  ax-i12 1533  ax-bndl 1535  ax-4 1536  ax-17 1552  ax-i9 1556  ax-ial 1560  ax-i5r 1561  ax-13 2182  ax-14 2183  ax-ext 2191  ax-sep 4181  ax-pow 4237  ax-pr 4272  ax-un 4501  ax-setind 4606  ax-cnex 8058  ax-resscn 8059  ax-1cn 8060  ax-1re 8061  ax-icn 8062  ax-addcl 8063  ax-addrcl 8064  ax-mulcl 8065  ax-addcom 8067  ax-addass 8069  ax-i2m1 8072  ax-0lt1 8073  ax-0id 8075  ax-rnegex 8076  ax-pre-ltirr 8079  ax-pre-ltadd 8083

This theorem depends on definitions:  df-bi 117  df-3an 985  df-tru 1378  df-fal 1381  df-nf 1487  df-sb 1789  df-eu 2060  df-mo 2061  df-clab 2196  df-cleq 2202  df-clel 2205  df-nfc 2341  df-ne 2381  df-nel 2476  df-ral 2493  df-rex 2494  df-reu 2495  df-rmo 2496  df-rab 2497  df-v 2781  df-sbc 3009  df-csb 3105  df-dif 3179  df-un 3181  df-in 3183  df-ss 3190  df-nul 3472  df-pw 3631  df-sn 3652  df-pr 3653  df-op 3655  df-uni 3868  df-int 3903  df-br 4063  df-opab 4125  df-mpt 4126  df-id 4361  df-xp 4702  df-rel 4703  df-cnv 4704  df-co 4705  df-dm 4706  df-rn 4707  df-res 4708  df-ima 4709  df-iota 5254  df-fun 5296  df-fn 5297  df-fv 5302  df-riota 5927  df-ov 5977  df-oprab 5978  df-mpo 5979  df-pnf 8151  df-mnf 8152  df-ltxr 8154  df-inn 9079  df-2 9137  df-ndx 13001  df-slot 13002  df-base 13004  df-sets 13005  df-iress 13006  df-plusg 13089  df-0g 13257  df-mgm 13355  df-sgrp 13401  df-mnd 13416  df-grp 13502  df-subg 13673

This theorem is referenced by:  subginv  13684  subg0cl  13685  subgmulg  13691  subrng0  14136  subrg0  14157  mpl0fi  14631