Proof of Theorem rhmmul
| Step | Hyp | Ref
 | Expression | 
| 1 |   | eqid 2196 | 
. . . . 5
⊢
(mulGrp‘𝑅) =
(mulGrp‘𝑅) | 
| 2 |   | eqid 2196 | 
. . . . 5
⊢
(mulGrp‘𝑆) =
(mulGrp‘𝑆) | 
| 3 | 1, 2 | rhmmhm 13715 | 
. . . 4
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → 𝐹 ∈ ((mulGrp‘𝑅) MndHom (mulGrp‘𝑆))) | 
| 4 | 3 | 3ad2ant1 1020 | 
. . 3
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐹 ∈ ((mulGrp‘𝑅) MndHom (mulGrp‘𝑆))) | 
| 5 |   | simp2 1000 | 
. . . 4
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐴 ∈ 𝑋) | 
| 6 |   | rhmrcl1 13711 | 
. . . . . . 7
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → 𝑅 ∈ Ring) | 
| 7 |   | rhmmul.x | 
. . . . . . . 8
⊢ 𝑋 = (Base‘𝑅) | 
| 8 | 1, 7 | mgpbasg 13482 | 
. . . . . . 7
⊢ (𝑅 ∈ Ring → 𝑋 =
(Base‘(mulGrp‘𝑅))) | 
| 9 | 6, 8 | syl 14 | 
. . . . . 6
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → 𝑋 = (Base‘(mulGrp‘𝑅))) | 
| 10 | 9 | eleq2d 2266 | 
. . . . 5
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → (𝐴 ∈ 𝑋 ↔ 𝐴 ∈ (Base‘(mulGrp‘𝑅)))) | 
| 11 | 10 | 3ad2ant1 1020 | 
. . . 4
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐴 ∈ 𝑋 ↔ 𝐴 ∈ (Base‘(mulGrp‘𝑅)))) | 
| 12 | 5, 11 | mpbid 147 | 
. . 3
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐴 ∈ (Base‘(mulGrp‘𝑅))) | 
| 13 |   | simp3 1001 | 
. . . 4
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐵 ∈ 𝑋) | 
| 14 | 9 | eleq2d 2266 | 
. . . . 5
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → (𝐵 ∈ 𝑋 ↔ 𝐵 ∈ (Base‘(mulGrp‘𝑅)))) | 
| 15 | 14 | 3ad2ant1 1020 | 
. . . 4
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐵 ∈ 𝑋 ↔ 𝐵 ∈ (Base‘(mulGrp‘𝑅)))) | 
| 16 | 13, 15 | mpbid 147 | 
. . 3
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐵 ∈ (Base‘(mulGrp‘𝑅))) | 
| 17 |   | eqid 2196 | 
. . . 4
⊢
(Base‘(mulGrp‘𝑅)) = (Base‘(mulGrp‘𝑅)) | 
| 18 |   | eqid 2196 | 
. . . 4
⊢
(+g‘(mulGrp‘𝑅)) =
(+g‘(mulGrp‘𝑅)) | 
| 19 |   | eqid 2196 | 
. . . 4
⊢
(+g‘(mulGrp‘𝑆)) =
(+g‘(mulGrp‘𝑆)) | 
| 20 | 17, 18, 19 | mhmlin 13099 | 
. . 3
⊢ ((𝐹 ∈ ((mulGrp‘𝑅) MndHom (mulGrp‘𝑆)) ∧ 𝐴 ∈ (Base‘(mulGrp‘𝑅)) ∧ 𝐵 ∈ (Base‘(mulGrp‘𝑅))) → (𝐹‘(𝐴(+g‘(mulGrp‘𝑅))𝐵)) = ((𝐹‘𝐴)(+g‘(mulGrp‘𝑆))(𝐹‘𝐵))) | 
| 21 | 4, 12, 16, 20 | syl3anc 1249 | 
. 2
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐹‘(𝐴(+g‘(mulGrp‘𝑅))𝐵)) = ((𝐹‘𝐴)(+g‘(mulGrp‘𝑆))(𝐹‘𝐵))) | 
| 22 |   | rhmmul.m | 
. . . . . . . 8
⊢  · =
(.r‘𝑅) | 
| 23 | 1, 22 | mgpplusgg 13480 | 
. . . . . . 7
⊢ (𝑅 ∈ Ring → · =
(+g‘(mulGrp‘𝑅))) | 
| 24 | 6, 23 | syl 14 | 
. . . . . 6
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → · =
(+g‘(mulGrp‘𝑅))) | 
| 25 | 24 | oveqd 5939 | 
. . . . 5
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → (𝐴 · 𝐵) = (𝐴(+g‘(mulGrp‘𝑅))𝐵)) | 
| 26 | 25 | fveq2d 5562 | 
. . . 4
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → (𝐹‘(𝐴 · 𝐵)) = (𝐹‘(𝐴(+g‘(mulGrp‘𝑅))𝐵))) | 
| 27 |   | rhmrcl2 13712 | 
. . . . . 6
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → 𝑆 ∈ Ring) | 
| 28 |   | rhmmul.n | 
. . . . . . 7
⊢  × =
(.r‘𝑆) | 
| 29 | 2, 28 | mgpplusgg 13480 | 
. . . . . 6
⊢ (𝑆 ∈ Ring → × =
(+g‘(mulGrp‘𝑆))) | 
| 30 | 27, 29 | syl 14 | 
. . . . 5
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → × =
(+g‘(mulGrp‘𝑆))) | 
| 31 | 30 | oveqd 5939 | 
. . . 4
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → ((𝐹‘𝐴) × (𝐹‘𝐵)) = ((𝐹‘𝐴)(+g‘(mulGrp‘𝑆))(𝐹‘𝐵))) | 
| 32 | 26, 31 | eqeq12d 2211 | 
. . 3
⊢ (𝐹 ∈ (𝑅 RingHom 𝑆) → ((𝐹‘(𝐴 · 𝐵)) = ((𝐹‘𝐴) × (𝐹‘𝐵)) ↔ (𝐹‘(𝐴(+g‘(mulGrp‘𝑅))𝐵)) = ((𝐹‘𝐴)(+g‘(mulGrp‘𝑆))(𝐹‘𝐵)))) | 
| 33 | 32 | 3ad2ant1 1020 | 
. 2
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → ((𝐹‘(𝐴 · 𝐵)) = ((𝐹‘𝐴) × (𝐹‘𝐵)) ↔ (𝐹‘(𝐴(+g‘(mulGrp‘𝑅))𝐵)) = ((𝐹‘𝐴)(+g‘(mulGrp‘𝑆))(𝐹‘𝐵)))) | 
| 34 | 21, 33 | mpbird 167 | 
1
⊢ ((𝐹 ∈ (𝑅 RingHom 𝑆) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐹‘(𝐴 · 𝐵)) = ((𝐹‘𝐴) × (𝐹‘𝐵))) |