| Step | Hyp | Ref
 | Expression | 
| 1 |   | simp1 999 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → 𝑅 ∈ Rng) | 
| 2 |   | rnglidlabl.l | 
. . . . . . . . 9
⊢ 𝐿 = (LIdeal‘𝑅) | 
| 3 |   | rnglidlabl.i | 
. . . . . . . . 9
⊢ 𝐼 = (𝑅 ↾s 𝑈) | 
| 4 | 2, 3 | lidlbas 14034 | 
. . . . . . . 8
⊢ (𝑈 ∈ 𝐿 → (Base‘𝐼) = 𝑈) | 
| 5 |   | eleq1a 2268 | 
. . . . . . . 8
⊢ (𝑈 ∈ 𝐿 → ((Base‘𝐼) = 𝑈 → (Base‘𝐼) ∈ 𝐿)) | 
| 6 | 4, 5 | mpd 13 | 
. . . . . . 7
⊢ (𝑈 ∈ 𝐿 → (Base‘𝐼) ∈ 𝐿) | 
| 7 | 6 | 3ad2ant2 1021 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (Base‘𝐼) ∈ 𝐿) | 
| 8 | 4 | eqcomd 2202 | 
. . . . . . . . 9
⊢ (𝑈 ∈ 𝐿 → 𝑈 = (Base‘𝐼)) | 
| 9 | 8 | eleq2d 2266 | 
. . . . . . . 8
⊢ (𝑈 ∈ 𝐿 → ( 0 ∈ 𝑈 ↔ 0 ∈ (Base‘𝐼))) | 
| 10 | 9 | biimpa 296 | 
. . . . . . 7
⊢ ((𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → 0 ∈ (Base‘𝐼)) | 
| 11 | 10 | 3adant1 1017 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → 0 ∈ (Base‘𝐼)) | 
| 12 | 1, 7, 11 | 3jca 1179 | 
. . . . 5
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (𝑅 ∈ Rng ∧ (Base‘𝐼) ∈ 𝐿 ∧ 0 ∈ (Base‘𝐼))) | 
| 13 | 2, 3 | lidlssbas 14033 | 
. . . . . . . . 9
⊢ (𝑈 ∈ 𝐿 → (Base‘𝐼) ⊆ (Base‘𝑅)) | 
| 14 | 13 | sseld 3182 | 
. . . . . . . 8
⊢ (𝑈 ∈ 𝐿 → (𝑎 ∈ (Base‘𝐼) → 𝑎 ∈ (Base‘𝑅))) | 
| 15 | 14 | 3ad2ant2 1021 | 
. . . . . . 7
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (𝑎 ∈ (Base‘𝐼) → 𝑎 ∈ (Base‘𝑅))) | 
| 16 | 15 | anim1d 336 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ((𝑎 ∈ (Base‘𝐼) ∧ 𝑏 ∈ (Base‘𝐼)) → (𝑎 ∈ (Base‘𝑅) ∧ 𝑏 ∈ (Base‘𝐼)))) | 
| 17 | 16 | imp 124 | 
. . . . 5
⊢ (((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) ∧ (𝑎 ∈ (Base‘𝐼) ∧ 𝑏 ∈ (Base‘𝐼))) → (𝑎 ∈ (Base‘𝑅) ∧ 𝑏 ∈ (Base‘𝐼))) | 
| 18 |   | rnglidlabl.z | 
. . . . . 6
⊢  0 =
(0g‘𝑅) | 
| 19 |   | eqid 2196 | 
. . . . . 6
⊢
(Base‘𝑅) =
(Base‘𝑅) | 
| 20 |   | eqid 2196 | 
. . . . . 6
⊢
(.r‘𝑅) = (.r‘𝑅) | 
| 21 | 18, 19, 20, 2 | rnglidlmcl 14036 | 
. . . . 5
⊢ (((𝑅 ∈ Rng ∧
(Base‘𝐼) ∈ 𝐿 ∧ 0 ∈ (Base‘𝐼)) ∧ (𝑎 ∈ (Base‘𝑅) ∧ 𝑏 ∈ (Base‘𝐼))) → (𝑎(.r‘𝑅)𝑏) ∈ (Base‘𝐼)) | 
| 22 | 12, 17, 21 | syl2an2r 595 | 
. . . 4
⊢ (((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) ∧ (𝑎 ∈ (Base‘𝐼) ∧ 𝑏 ∈ (Base‘𝐼))) → (𝑎(.r‘𝑅)𝑏) ∈ (Base‘𝐼)) | 
| 23 |   | simp2 1000 | 
. . . . . . . . 9
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → 𝑈 ∈ 𝐿) | 
| 24 | 3, 20 | ressmulrg 12822 | 
. . . . . . . . 9
⊢ ((𝑈 ∈ 𝐿 ∧ 𝑅 ∈ Rng) →
(.r‘𝑅) =
(.r‘𝐼)) | 
| 25 | 23, 1, 24 | syl2anc 411 | 
. . . . . . . 8
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (.r‘𝑅) = (.r‘𝐼)) | 
| 26 | 25 | eqcomd 2202 | 
. . . . . . 7
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (.r‘𝐼) = (.r‘𝑅)) | 
| 27 | 26 | oveqd 5939 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (𝑎(.r‘𝐼)𝑏) = (𝑎(.r‘𝑅)𝑏)) | 
| 28 | 27 | eleq1d 2265 | 
. . . . 5
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ((𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼) ↔ (𝑎(.r‘𝑅)𝑏) ∈ (Base‘𝐼))) | 
| 29 | 28 | adantr 276 | 
. . . 4
⊢ (((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) ∧ (𝑎 ∈ (Base‘𝐼) ∧ 𝑏 ∈ (Base‘𝐼))) → ((𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼) ↔ (𝑎(.r‘𝑅)𝑏) ∈ (Base‘𝐼))) | 
| 30 | 22, 29 | mpbird 167 | 
. . 3
⊢ (((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) ∧ (𝑎 ∈ (Base‘𝐼) ∧ 𝑏 ∈ (Base‘𝐼))) → (𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼)) | 
| 31 | 30 | ralrimivva 2579 | 
. 2
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ∀𝑎 ∈ (Base‘𝐼)∀𝑏 ∈ (Base‘𝐼)(𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼)) | 
| 32 |   | ressex 12743 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿) → (𝑅 ↾s 𝑈) ∈ V) | 
| 33 | 3, 32 | eqeltrid 2283 | 
. . . . 5
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿) → 𝐼 ∈ V) | 
| 34 | 1, 23, 33 | syl2anc 411 | 
. . . 4
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → 𝐼 ∈ V) | 
| 35 |   | eqid 2196 | 
. . . . 5
⊢
(mulGrp‘𝐼) =
(mulGrp‘𝐼) | 
| 36 | 35 | mgpex 13481 | 
. . . 4
⊢ (𝐼 ∈ V →
(mulGrp‘𝐼) ∈
V) | 
| 37 |   | eqid 2196 | 
. . . . 5
⊢
(Base‘(mulGrp‘𝐼)) = (Base‘(mulGrp‘𝐼)) | 
| 38 |   | eqid 2196 | 
. . . . 5
⊢
(+g‘(mulGrp‘𝐼)) =
(+g‘(mulGrp‘𝐼)) | 
| 39 | 37, 38 | ismgm 13000 | 
. . . 4
⊢
((mulGrp‘𝐼)
∈ V → ((mulGrp‘𝐼) ∈ Mgm ↔ ∀𝑎 ∈
(Base‘(mulGrp‘𝐼))∀𝑏 ∈ (Base‘(mulGrp‘𝐼))(𝑎(+g‘(mulGrp‘𝐼))𝑏) ∈ (Base‘(mulGrp‘𝐼)))) | 
| 40 | 34, 36, 39 | 3syl 17 | 
. . 3
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ((mulGrp‘𝐼) ∈ Mgm ↔ ∀𝑎 ∈
(Base‘(mulGrp‘𝐼))∀𝑏 ∈ (Base‘(mulGrp‘𝐼))(𝑎(+g‘(mulGrp‘𝐼))𝑏) ∈ (Base‘(mulGrp‘𝐼)))) | 
| 41 |   | eqid 2196 | 
. . . . . 6
⊢
(Base‘𝐼) =
(Base‘𝐼) | 
| 42 | 35, 41 | mgpbasg 13482 | 
. . . . 5
⊢ (𝐼 ∈ V →
(Base‘𝐼) =
(Base‘(mulGrp‘𝐼))) | 
| 43 | 34, 42 | syl 14 | 
. . . 4
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (Base‘𝐼) = (Base‘(mulGrp‘𝐼))) | 
| 44 |   | eqid 2196 | 
. . . . . . . . 9
⊢
(.r‘𝐼) = (.r‘𝐼) | 
| 45 | 35, 44 | mgpplusgg 13480 | 
. . . . . . . 8
⊢ (𝐼 ∈ V →
(.r‘𝐼) =
(+g‘(mulGrp‘𝐼))) | 
| 46 | 34, 45 | syl 14 | 
. . . . . . 7
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (.r‘𝐼) =
(+g‘(mulGrp‘𝐼))) | 
| 47 | 46 | oveqd 5939 | 
. . . . . 6
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (𝑎(.r‘𝐼)𝑏) = (𝑎(+g‘(mulGrp‘𝐼))𝑏)) | 
| 48 | 47, 43 | eleq12d 2267 | 
. . . . 5
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ((𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼) ↔ (𝑎(+g‘(mulGrp‘𝐼))𝑏) ∈ (Base‘(mulGrp‘𝐼)))) | 
| 49 | 43, 48 | raleqbidv 2709 | 
. . . 4
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (∀𝑏 ∈ (Base‘𝐼)(𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼) ↔ ∀𝑏 ∈ (Base‘(mulGrp‘𝐼))(𝑎(+g‘(mulGrp‘𝐼))𝑏) ∈ (Base‘(mulGrp‘𝐼)))) | 
| 50 | 43, 49 | raleqbidv 2709 | 
. . 3
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (∀𝑎 ∈ (Base‘𝐼)∀𝑏 ∈ (Base‘𝐼)(𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼) ↔ ∀𝑎 ∈ (Base‘(mulGrp‘𝐼))∀𝑏 ∈ (Base‘(mulGrp‘𝐼))(𝑎(+g‘(mulGrp‘𝐼))𝑏) ∈ (Base‘(mulGrp‘𝐼)))) | 
| 51 | 40, 50 | bitr4d 191 | 
. 2
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → ((mulGrp‘𝐼) ∈ Mgm ↔ ∀𝑎 ∈ (Base‘𝐼)∀𝑏 ∈ (Base‘𝐼)(𝑎(.r‘𝐼)𝑏) ∈ (Base‘𝐼))) | 
| 52 | 31, 51 | mpbird 167 | 
1
⊢ ((𝑅 ∈ Rng ∧ 𝑈 ∈ 𝐿 ∧ 0 ∈ 𝑈) → (mulGrp‘𝐼) ∈ Mgm) |