| Step | Hyp | Ref
 | Expression | 
| 1 |   | elnmz.1 | 
. . . 4
⊢ 𝑁 = {𝑥 ∈ 𝑋 ∣ ∀𝑦 ∈ 𝑋 ((𝑥 + 𝑦) ∈ 𝑆 ↔ (𝑦 + 𝑥) ∈ 𝑆)} | 
| 2 | 1 | ssrab3 3269 | 
. . 3
⊢ 𝑁 ⊆ 𝑋 | 
| 3 | 2 | a1i 9 | 
. 2
⊢ (𝐺 ∈ Grp → 𝑁 ⊆ 𝑋) | 
| 4 |   | nmzsubg.2 | 
. . . . 5
⊢ 𝑋 = (Base‘𝐺) | 
| 5 |   | eqid 2196 | 
. . . . 5
⊢
(0g‘𝐺) = (0g‘𝐺) | 
| 6 | 4, 5 | grpidcl 13161 | 
. . . 4
⊢ (𝐺 ∈ Grp →
(0g‘𝐺)
∈ 𝑋) | 
| 7 |   | nmzsubg.3 | 
. . . . . . . 8
⊢  + =
(+g‘𝐺) | 
| 8 | 4, 7, 5 | grplid 13163 | 
. . . . . . 7
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → ((0g‘𝐺) + 𝑧) = 𝑧) | 
| 9 | 4, 7, 5 | grprid 13164 | 
. . . . . . 7
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → (𝑧 + (0g‘𝐺)) = 𝑧) | 
| 10 | 8, 9 | eqtr4d 2232 | 
. . . . . 6
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → ((0g‘𝐺) + 𝑧) = (𝑧 + (0g‘𝐺))) | 
| 11 | 10 | eleq1d 2265 | 
. . . . 5
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → (((0g‘𝐺) + 𝑧) ∈ 𝑆 ↔ (𝑧 + (0g‘𝐺)) ∈ 𝑆)) | 
| 12 | 11 | ralrimiva 2570 | 
. . . 4
⊢ (𝐺 ∈ Grp → ∀𝑧 ∈ 𝑋 (((0g‘𝐺) + 𝑧) ∈ 𝑆 ↔ (𝑧 + (0g‘𝐺)) ∈ 𝑆)) | 
| 13 | 1 | elnmz 13338 | 
. . . 4
⊢
((0g‘𝐺) ∈ 𝑁 ↔ ((0g‘𝐺) ∈ 𝑋 ∧ ∀𝑧 ∈ 𝑋 (((0g‘𝐺) + 𝑧) ∈ 𝑆 ↔ (𝑧 + (0g‘𝐺)) ∈ 𝑆))) | 
| 14 | 6, 12, 13 | sylanbrc 417 | 
. . 3
⊢ (𝐺 ∈ Grp →
(0g‘𝐺)
∈ 𝑁) | 
| 15 |   | elex2 2779 | 
. . 3
⊢
((0g‘𝐺) ∈ 𝑁 → ∃𝑎 𝑎 ∈ 𝑁) | 
| 16 | 14, 15 | syl 14 | 
. 2
⊢ (𝐺 ∈ Grp → ∃𝑎 𝑎 ∈ 𝑁) | 
| 17 |   | id 19 | 
. . . . . . . 8
⊢ (𝐺 ∈ Grp → 𝐺 ∈ Grp) | 
| 18 | 2 | sseli 3179 | 
. . . . . . . 8
⊢ (𝑧 ∈ 𝑁 → 𝑧 ∈ 𝑋) | 
| 19 | 2 | sseli 3179 | 
. . . . . . . 8
⊢ (𝑤 ∈ 𝑁 → 𝑤 ∈ 𝑋) | 
| 20 | 4, 7 | grpcl 13140 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋 ∧ 𝑤 ∈ 𝑋) → (𝑧 + 𝑤) ∈ 𝑋) | 
| 21 | 17, 18, 19, 20 | syl3an 1291 | 
. . . . . . 7
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) → (𝑧 + 𝑤) ∈ 𝑋) | 
| 22 |   | simpl1 1002 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝐺 ∈ Grp) | 
| 23 |   | simpl2 1003 | 
. . . . . . . . . . . 12
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑧 ∈ 𝑁) | 
| 24 | 2, 23 | sselid 3181 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑧 ∈ 𝑋) | 
| 25 |   | simpl3 1004 | 
. . . . . . . . . . . 12
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑤 ∈ 𝑁) | 
| 26 | 2, 25 | sselid 3181 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑤 ∈ 𝑋) | 
| 27 |   | simpr 110 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑢 ∈ 𝑋) | 
| 28 | 4, 7 | grpass 13141 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ (𝑧 ∈ 𝑋 ∧ 𝑤 ∈ 𝑋 ∧ 𝑢 ∈ 𝑋)) → ((𝑧 + 𝑤) + 𝑢) = (𝑧 + (𝑤 + 𝑢))) | 
| 29 | 22, 24, 26, 27, 28 | syl13anc 1251 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 + 𝑤) + 𝑢) = (𝑧 + (𝑤 + 𝑢))) | 
| 30 | 29 | eleq1d 2265 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((𝑧 + 𝑤) + 𝑢) ∈ 𝑆 ↔ (𝑧 + (𝑤 + 𝑢)) ∈ 𝑆)) | 
| 31 | 4, 7, 22, 26, 27 | grpcld 13146 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑤 + 𝑢) ∈ 𝑋) | 
| 32 | 1 | nmzbi 13339 | 
. . . . . . . . . . 11
⊢ ((𝑧 ∈ 𝑁 ∧ (𝑤 + 𝑢) ∈ 𝑋) → ((𝑧 + (𝑤 + 𝑢)) ∈ 𝑆 ↔ ((𝑤 + 𝑢) + 𝑧) ∈ 𝑆)) | 
| 33 | 23, 31, 32 | syl2anc 411 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 + (𝑤 + 𝑢)) ∈ 𝑆 ↔ ((𝑤 + 𝑢) + 𝑧) ∈ 𝑆)) | 
| 34 | 4, 7 | grpass 13141 | 
. . . . . . . . . . . 12
⊢ ((𝐺 ∈ Grp ∧ (𝑤 ∈ 𝑋 ∧ 𝑢 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋)) → ((𝑤 + 𝑢) + 𝑧) = (𝑤 + (𝑢 + 𝑧))) | 
| 35 | 22, 26, 27, 24, 34 | syl13anc 1251 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑤 + 𝑢) + 𝑧) = (𝑤 + (𝑢 + 𝑧))) | 
| 36 | 35 | eleq1d 2265 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((𝑤 + 𝑢) + 𝑧) ∈ 𝑆 ↔ (𝑤 + (𝑢 + 𝑧)) ∈ 𝑆)) | 
| 37 | 4, 7, 22, 27, 24 | grpcld 13146 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑢 + 𝑧) ∈ 𝑋) | 
| 38 | 1 | nmzbi 13339 | 
. . . . . . . . . . 11
⊢ ((𝑤 ∈ 𝑁 ∧ (𝑢 + 𝑧) ∈ 𝑋) → ((𝑤 + (𝑢 + 𝑧)) ∈ 𝑆 ↔ ((𝑢 + 𝑧) + 𝑤) ∈ 𝑆)) | 
| 39 | 25, 37, 38 | syl2anc 411 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑤 + (𝑢 + 𝑧)) ∈ 𝑆 ↔ ((𝑢 + 𝑧) + 𝑤) ∈ 𝑆)) | 
| 40 | 33, 36, 39 | 3bitrd 214 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 + (𝑤 + 𝑢)) ∈ 𝑆 ↔ ((𝑢 + 𝑧) + 𝑤) ∈ 𝑆)) | 
| 41 | 4, 7 | grpass 13141 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ (𝑢 ∈ 𝑋 ∧ 𝑧 ∈ 𝑋 ∧ 𝑤 ∈ 𝑋)) → ((𝑢 + 𝑧) + 𝑤) = (𝑢 + (𝑧 + 𝑤))) | 
| 42 | 22, 27, 24, 26, 41 | syl13anc 1251 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑢 + 𝑧) + 𝑤) = (𝑢 + (𝑧 + 𝑤))) | 
| 43 | 42 | eleq1d 2265 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((𝑢 + 𝑧) + 𝑤) ∈ 𝑆 ↔ (𝑢 + (𝑧 + 𝑤)) ∈ 𝑆)) | 
| 44 | 30, 40, 43 | 3bitrd 214 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((𝑧 + 𝑤) + 𝑢) ∈ 𝑆 ↔ (𝑢 + (𝑧 + 𝑤)) ∈ 𝑆)) | 
| 45 | 44 | ralrimiva 2570 | 
. . . . . . 7
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) → ∀𝑢 ∈ 𝑋 (((𝑧 + 𝑤) + 𝑢) ∈ 𝑆 ↔ (𝑢 + (𝑧 + 𝑤)) ∈ 𝑆)) | 
| 46 | 1 | elnmz 13338 | 
. . . . . . 7
⊢ ((𝑧 + 𝑤) ∈ 𝑁 ↔ ((𝑧 + 𝑤) ∈ 𝑋 ∧ ∀𝑢 ∈ 𝑋 (((𝑧 + 𝑤) + 𝑢) ∈ 𝑆 ↔ (𝑢 + (𝑧 + 𝑤)) ∈ 𝑆))) | 
| 47 | 21, 45, 46 | sylanbrc 417 | 
. . . . . 6
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁 ∧ 𝑤 ∈ 𝑁) → (𝑧 + 𝑤) ∈ 𝑁) | 
| 48 | 47 | 3expa 1205 | 
. . . . 5
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑤 ∈ 𝑁) → (𝑧 + 𝑤) ∈ 𝑁) | 
| 49 | 48 | ralrimiva 2570 | 
. . . 4
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) → ∀𝑤 ∈ 𝑁 (𝑧 + 𝑤) ∈ 𝑁) | 
| 50 |   | eqid 2196 | 
. . . . . . 7
⊢
(invg‘𝐺) = (invg‘𝐺) | 
| 51 | 4, 50 | grpinvcl 13180 | 
. . . . . 6
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → ((invg‘𝐺)‘𝑧) ∈ 𝑋) | 
| 52 | 18, 51 | sylan2 286 | 
. . . . 5
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) → ((invg‘𝐺)‘𝑧) ∈ 𝑋) | 
| 53 |   | simplr 528 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑧 ∈ 𝑁) | 
| 54 |   | simpll 527 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝐺 ∈ Grp) | 
| 55 | 52 | adantr 276 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((invg‘𝐺)‘𝑧) ∈ 𝑋) | 
| 56 |   | simpr 110 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑢 ∈ 𝑋) | 
| 57 | 4, 7, 54, 56, 55 | grpcld 13146 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑋) | 
| 58 | 4, 7, 54, 55, 57 | grpcld 13146 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) ∈ 𝑋) | 
| 59 | 1 | nmzbi 13339 | 
. . . . . . . 8
⊢ ((𝑧 ∈ 𝑁 ∧ (((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) ∈ 𝑋) → ((𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧)))) ∈ 𝑆 ↔ ((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) ∈ 𝑆)) | 
| 60 | 53, 58, 59 | syl2anc 411 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧)))) ∈ 𝑆 ↔ ((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) ∈ 𝑆)) | 
| 61 | 2, 53 | sselid 3181 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → 𝑧 ∈ 𝑋) | 
| 62 | 4, 7, 5, 50 | grprinv 13183 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → (𝑧 +
((invg‘𝐺)‘𝑧)) = (0g‘𝐺)) | 
| 63 | 54, 61, 62 | syl2anc 411 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑧 +
((invg‘𝐺)‘𝑧)) = (0g‘𝐺)) | 
| 64 | 63 | oveq1d 5937 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 +
((invg‘𝐺)‘𝑧)) + (𝑢 +
((invg‘𝐺)‘𝑧))) = ((0g‘𝐺) + (𝑢 +
((invg‘𝐺)‘𝑧)))) | 
| 65 | 4, 7 | grpass 13141 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑧 ∈ 𝑋 ∧ ((invg‘𝐺)‘𝑧) ∈ 𝑋 ∧ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑋)) → ((𝑧 +
((invg‘𝐺)‘𝑧)) + (𝑢 +
((invg‘𝐺)‘𝑧))) = (𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))))) | 
| 66 | 54, 61, 55, 57, 65 | syl13anc 1251 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 +
((invg‘𝐺)‘𝑧)) + (𝑢 +
((invg‘𝐺)‘𝑧))) = (𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))))) | 
| 67 | 4, 7, 5 | grplid 13163 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑋) → ((0g‘𝐺) + (𝑢 +
((invg‘𝐺)‘𝑧))) = (𝑢 +
((invg‘𝐺)‘𝑧))) | 
| 68 | 54, 57, 67 | syl2anc 411 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((0g‘𝐺) + (𝑢 +
((invg‘𝐺)‘𝑧))) = (𝑢 +
((invg‘𝐺)‘𝑧))) | 
| 69 | 64, 66, 68 | 3eqtr3d 2237 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧)))) = (𝑢 +
((invg‘𝐺)‘𝑧))) | 
| 70 | 69 | eleq1d 2265 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑧 +
(((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧)))) ∈ 𝑆 ↔ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑆)) | 
| 71 | 4, 7 | grpass 13141 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧
(((invg‘𝐺)‘𝑧) ∈ 𝑋 ∧ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑋 ∧ 𝑧 ∈ 𝑋)) → ((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) = (((invg‘𝐺)‘𝑧) + ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧))) | 
| 72 | 54, 55, 57, 61, 71 | syl13anc 1251 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) = (((invg‘𝐺)‘𝑧) + ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧))) | 
| 73 | 4, 7 | grpass 13141 | 
. . . . . . . . . . . 12
⊢ ((𝐺 ∈ Grp ∧ (𝑢 ∈ 𝑋 ∧ ((invg‘𝐺)‘𝑧) ∈ 𝑋 ∧ 𝑧 ∈ 𝑋)) → ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧) = (𝑢 +
(((invg‘𝐺)‘𝑧) + 𝑧))) | 
| 74 | 54, 56, 55, 61, 73 | syl13anc 1251 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧) = (𝑢 +
(((invg‘𝐺)‘𝑧) + 𝑧))) | 
| 75 | 4, 7, 5, 50 | grplinv 13182 | 
. . . . . . . . . . . . 13
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑋) → (((invg‘𝐺)‘𝑧) + 𝑧) = (0g‘𝐺)) | 
| 76 | 54, 61, 75 | syl2anc 411 | 
. . . . . . . . . . . 12
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((invg‘𝐺)‘𝑧) + 𝑧) = (0g‘𝐺)) | 
| 77 | 76 | oveq2d 5938 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑢 +
(((invg‘𝐺)‘𝑧) + 𝑧)) = (𝑢 + (0g‘𝐺))) | 
| 78 | 4, 7, 5 | grprid 13164 | 
. . . . . . . . . . . 12
⊢ ((𝐺 ∈ Grp ∧ 𝑢 ∈ 𝑋) → (𝑢 + (0g‘𝐺)) = 𝑢) | 
| 79 | 54, 56, 78 | syl2anc 411 | 
. . . . . . . . . . 11
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (𝑢 + (0g‘𝐺)) = 𝑢) | 
| 80 | 74, 77, 79 | 3eqtrd 2233 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧) = 𝑢) | 
| 81 | 80 | oveq2d 5938 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((invg‘𝐺)‘𝑧) + ((𝑢 +
((invg‘𝐺)‘𝑧)) + 𝑧)) = (((invg‘𝐺)‘𝑧) + 𝑢)) | 
| 82 | 72, 81 | eqtrd 2229 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) = (((invg‘𝐺)‘𝑧) + 𝑢)) | 
| 83 | 82 | eleq1d 2265 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → (((((invg‘𝐺)‘𝑧) + (𝑢 +
((invg‘𝐺)‘𝑧))) + 𝑧) ∈ 𝑆 ↔ (((invg‘𝐺)‘𝑧) + 𝑢) ∈ 𝑆)) | 
| 84 | 60, 70, 83 | 3bitr3rd 219 | 
. . . . . 6
⊢ (((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) ∧ 𝑢 ∈ 𝑋) → ((((invg‘𝐺)‘𝑧) + 𝑢) ∈ 𝑆 ↔ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑆)) | 
| 85 | 84 | ralrimiva 2570 | 
. . . . 5
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) → ∀𝑢 ∈ 𝑋 ((((invg‘𝐺)‘𝑧) + 𝑢) ∈ 𝑆 ↔ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑆)) | 
| 86 | 1 | elnmz 13338 | 
. . . . 5
⊢
(((invg‘𝐺)‘𝑧) ∈ 𝑁 ↔ (((invg‘𝐺)‘𝑧) ∈ 𝑋 ∧ ∀𝑢 ∈ 𝑋 ((((invg‘𝐺)‘𝑧) + 𝑢) ∈ 𝑆 ↔ (𝑢 +
((invg‘𝐺)‘𝑧)) ∈ 𝑆))) | 
| 87 | 52, 85, 86 | sylanbrc 417 | 
. . . 4
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) → ((invg‘𝐺)‘𝑧) ∈ 𝑁) | 
| 88 | 49, 87 | jca 306 | 
. . 3
⊢ ((𝐺 ∈ Grp ∧ 𝑧 ∈ 𝑁) → (∀𝑤 ∈ 𝑁 (𝑧 + 𝑤) ∈ 𝑁 ∧ ((invg‘𝐺)‘𝑧) ∈ 𝑁)) | 
| 89 | 88 | ralrimiva 2570 | 
. 2
⊢ (𝐺 ∈ Grp → ∀𝑧 ∈ 𝑁 (∀𝑤 ∈ 𝑁 (𝑧 + 𝑤) ∈ 𝑁 ∧ ((invg‘𝐺)‘𝑧) ∈ 𝑁)) | 
| 90 | 4, 7, 50 | issubg2m 13319 | 
. 2
⊢ (𝐺 ∈ Grp → (𝑁 ∈ (SubGrp‘𝐺) ↔ (𝑁 ⊆ 𝑋 ∧ ∃𝑎 𝑎 ∈ 𝑁 ∧ ∀𝑧 ∈ 𝑁 (∀𝑤 ∈ 𝑁 (𝑧 + 𝑤) ∈ 𝑁 ∧ ((invg‘𝐺)‘𝑧) ∈ 𝑁)))) | 
| 91 | 3, 16, 89, 90 | mpbir3and 1182 | 
1
⊢ (𝐺 ∈ Grp → 𝑁 ∈ (SubGrp‘𝐺)) |