| Step | Hyp | Ref
 | Expression | 
| 1 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑥 = 0 → (𝑥 · 𝑋) = (0 · 𝑋)) | 
| 2 | 1 | oveq1d 5937 | 
. . . . . 6
⊢ (𝑥 = 0 → ((𝑥 · 𝑋) × 𝑌) = ((0 · 𝑋) × 𝑌)) | 
| 3 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑥 = 0 → (𝑥 · (𝑋 × 𝑌)) = (0 · (𝑋 × 𝑌))) | 
| 4 | 2, 3 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑥 = 0 → (((𝑥 · 𝑋) × 𝑌) = (𝑥 · (𝑋 × 𝑌)) ↔ ((0 · 𝑋) × 𝑌) = (0 · (𝑋 × 𝑌)))) | 
| 5 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑥 = 𝑦 → (𝑥 · 𝑋) = (𝑦 · 𝑋)) | 
| 6 | 5 | oveq1d 5937 | 
. . . . . 6
⊢ (𝑥 = 𝑦 → ((𝑥 · 𝑋) × 𝑌) = ((𝑦 · 𝑋) × 𝑌)) | 
| 7 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑥 = 𝑦 → (𝑥 · (𝑋 × 𝑌)) = (𝑦 · (𝑋 × 𝑌))) | 
| 8 | 6, 7 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑥 = 𝑦 → (((𝑥 · 𝑋) × 𝑌) = (𝑥 · (𝑋 × 𝑌)) ↔ ((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)))) | 
| 9 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑥 = (𝑦 + 1) → (𝑥 · 𝑋) = ((𝑦 + 1) · 𝑋)) | 
| 10 | 9 | oveq1d 5937 | 
. . . . . 6
⊢ (𝑥 = (𝑦 + 1) → ((𝑥 · 𝑋) × 𝑌) = (((𝑦 + 1) · 𝑋) × 𝑌)) | 
| 11 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑥 = (𝑦 + 1) → (𝑥 · (𝑋 × 𝑌)) = ((𝑦 + 1) · (𝑋 × 𝑌))) | 
| 12 | 10, 11 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑥 = (𝑦 + 1) → (((𝑥 · 𝑋) × 𝑌) = (𝑥 · (𝑋 × 𝑌)) ↔ (((𝑦 + 1) · 𝑋) × 𝑌) = ((𝑦 + 1) · (𝑋 × 𝑌)))) | 
| 13 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑥 = -𝑦 → (𝑥 · 𝑋) = (-𝑦 · 𝑋)) | 
| 14 | 13 | oveq1d 5937 | 
. . . . . 6
⊢ (𝑥 = -𝑦 → ((𝑥 · 𝑋) × 𝑌) = ((-𝑦 · 𝑋) × 𝑌)) | 
| 15 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑥 = -𝑦 → (𝑥 · (𝑋 × 𝑌)) = (-𝑦 · (𝑋 × 𝑌))) | 
| 16 | 14, 15 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑥 = -𝑦 → (((𝑥 · 𝑋) × 𝑌) = (𝑥 · (𝑋 × 𝑌)) ↔ ((-𝑦 · 𝑋) × 𝑌) = (-𝑦 · (𝑋 × 𝑌)))) | 
| 17 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑥 = 𝑁 → (𝑥 · 𝑋) = (𝑁 · 𝑋)) | 
| 18 | 17 | oveq1d 5937 | 
. . . . . 6
⊢ (𝑥 = 𝑁 → ((𝑥 · 𝑋) × 𝑌) = ((𝑁 · 𝑋) × 𝑌)) | 
| 19 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑥 = 𝑁 → (𝑥 · (𝑋 × 𝑌)) = (𝑁 · (𝑋 × 𝑌))) | 
| 20 | 18, 19 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑥 = 𝑁 → (((𝑥 · 𝑋) × 𝑌) = (𝑥 · (𝑋 × 𝑌)) ↔ ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌)))) | 
| 21 |   | mulgass2.b | 
. . . . . . . 8
⊢ 𝐵 = (Base‘𝑅) | 
| 22 |   | mulgass2.t | 
. . . . . . . 8
⊢  × =
(.r‘𝑅) | 
| 23 |   | eqid 2196 | 
. . . . . . . 8
⊢
(0g‘𝑅) = (0g‘𝑅) | 
| 24 | 21, 22, 23 | ringlz 13599 | 
. . . . . . 7
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵) → ((0g‘𝑅) × 𝑌) = (0g‘𝑅)) | 
| 25 | 24 | 3adant3 1019 | 
. . . . . 6
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → ((0g‘𝑅) × 𝑌) = (0g‘𝑅)) | 
| 26 |   | simp3 1001 | 
. . . . . . . 8
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → 𝑋 ∈ 𝐵) | 
| 27 |   | mulgass2.m | 
. . . . . . . . 9
⊢  · =
(.g‘𝑅) | 
| 28 | 21, 23, 27 | mulg0 13255 | 
. . . . . . . 8
⊢ (𝑋 ∈ 𝐵 → (0 · 𝑋) = (0g‘𝑅)) | 
| 29 | 26, 28 | syl 14 | 
. . . . . . 7
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (0 · 𝑋) = (0g‘𝑅)) | 
| 30 | 29 | oveq1d 5937 | 
. . . . . 6
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → ((0 · 𝑋) × 𝑌) = ((0g‘𝑅) × 𝑌)) | 
| 31 | 21, 22 | ringcl 13569 | 
. . . . . . . 8
⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 × 𝑌) ∈ 𝐵) | 
| 32 | 31 | 3com23 1211 | 
. . . . . . 7
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (𝑋 × 𝑌) ∈ 𝐵) | 
| 33 | 21, 23, 27 | mulg0 13255 | 
. . . . . . 7
⊢ ((𝑋 × 𝑌) ∈ 𝐵 → (0 · (𝑋 × 𝑌)) = (0g‘𝑅)) | 
| 34 | 32, 33 | syl 14 | 
. . . . . 6
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (0 · (𝑋 × 𝑌)) = (0g‘𝑅)) | 
| 35 | 25, 30, 34 | 3eqtr4d 2239 | 
. . . . 5
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → ((0 · 𝑋) × 𝑌) = (0 · (𝑋 × 𝑌))) | 
| 36 |   | oveq1 5929 | 
. . . . . . 7
⊢ (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → (((𝑦 · 𝑋) × 𝑌)(+g‘𝑅)(𝑋 × 𝑌)) = ((𝑦 · (𝑋 × 𝑌))(+g‘𝑅)(𝑋 × 𝑌))) | 
| 37 |   | simpl1 1002 | 
. . . . . . . . . . . 12
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑅 ∈ Ring) | 
| 38 |   | ringgrp 13557 | 
. . . . . . . . . . . 12
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Grp) | 
| 39 | 37, 38 | syl 14 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑅 ∈ Grp) | 
| 40 |   | nn0z 9346 | 
. . . . . . . . . . . 12
⊢ (𝑦 ∈ ℕ0
→ 𝑦 ∈
ℤ) | 
| 41 | 40 | adantl 277 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑦 ∈
ℤ) | 
| 42 | 26 | adantr 276 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑋 ∈ 𝐵) | 
| 43 |   | eqid 2196 | 
. . . . . . . . . . . 12
⊢
(+g‘𝑅) = (+g‘𝑅) | 
| 44 | 21, 27, 43 | mulgp1 13285 | 
. . . . . . . . . . 11
⊢ ((𝑅 ∈ Grp ∧ 𝑦 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → ((𝑦 + 1) · 𝑋) = ((𝑦 · 𝑋)(+g‘𝑅)𝑋)) | 
| 45 | 39, 41, 42, 44 | syl3anc 1249 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → ((𝑦 + 1) · 𝑋) = ((𝑦 · 𝑋)(+g‘𝑅)𝑋)) | 
| 46 | 45 | oveq1d 5937 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (((𝑦 + 1) · 𝑋) × 𝑌) = (((𝑦 · 𝑋)(+g‘𝑅)𝑋) × 𝑌)) | 
| 47 | 38 | 3ad2ant1 1020 | 
. . . . . . . . . . . 12
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → 𝑅 ∈ Grp) | 
| 48 | 47 | adantr 276 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑅 ∈ Grp) | 
| 49 | 21, 27 | mulgcl 13269 | 
. . . . . . . . . . 11
⊢ ((𝑅 ∈ Grp ∧ 𝑦 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → (𝑦 · 𝑋) ∈ 𝐵) | 
| 50 | 48, 41, 42, 49 | syl3anc 1249 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (𝑦 · 𝑋) ∈ 𝐵) | 
| 51 |   | simpl2 1003 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → 𝑌 ∈ 𝐵) | 
| 52 | 21, 43, 22 | ringdir 13575 | 
. . . . . . . . . 10
⊢ ((𝑅 ∈ Ring ∧ ((𝑦 · 𝑋) ∈ 𝐵 ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵)) → (((𝑦 · 𝑋)(+g‘𝑅)𝑋) × 𝑌) = (((𝑦 · 𝑋) × 𝑌)(+g‘𝑅)(𝑋 × 𝑌))) | 
| 53 | 37, 50, 42, 51, 52 | syl13anc 1251 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (((𝑦 · 𝑋)(+g‘𝑅)𝑋) × 𝑌) = (((𝑦 · 𝑋) × 𝑌)(+g‘𝑅)(𝑋 × 𝑌))) | 
| 54 | 46, 53 | eqtrd 2229 | 
. . . . . . . 8
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (((𝑦 + 1) · 𝑋) × 𝑌) = (((𝑦 · 𝑋) × 𝑌)(+g‘𝑅)(𝑋 × 𝑌))) | 
| 55 | 32 | adantr 276 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (𝑋 × 𝑌) ∈ 𝐵) | 
| 56 | 21, 27, 43 | mulgp1 13285 | 
. . . . . . . . 9
⊢ ((𝑅 ∈ Grp ∧ 𝑦 ∈ ℤ ∧ (𝑋 × 𝑌) ∈ 𝐵) → ((𝑦 + 1) · (𝑋 × 𝑌)) = ((𝑦 · (𝑋 × 𝑌))(+g‘𝑅)(𝑋 × 𝑌))) | 
| 57 | 39, 41, 55, 56 | syl3anc 1249 | 
. . . . . . . 8
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → ((𝑦 + 1) · (𝑋 × 𝑌)) = ((𝑦 · (𝑋 × 𝑌))(+g‘𝑅)(𝑋 × 𝑌))) | 
| 58 | 54, 57 | eqeq12d 2211 | 
. . . . . . 7
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → ((((𝑦 + 1) · 𝑋) × 𝑌) = ((𝑦 + 1) · (𝑋 × 𝑌)) ↔ (((𝑦 · 𝑋) × 𝑌)(+g‘𝑅)(𝑋 × 𝑌)) = ((𝑦 · (𝑋 × 𝑌))(+g‘𝑅)(𝑋 × 𝑌)))) | 
| 59 | 36, 58 | imbitrrid 156 | 
. . . . . 6
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ0) → (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → (((𝑦 + 1) · 𝑋) × 𝑌) = ((𝑦 + 1) · (𝑋 × 𝑌)))) | 
| 60 | 59 | ex 115 | 
. . . . 5
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (𝑦 ∈ ℕ0 → (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → (((𝑦 + 1) · 𝑋) × 𝑌) = ((𝑦 + 1) · (𝑋 × 𝑌))))) | 
| 61 |   | fveq2 5558 | 
. . . . . . 7
⊢ (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → ((invg‘𝑅)‘((𝑦 · 𝑋) × 𝑌)) = ((invg‘𝑅)‘(𝑦 · (𝑋 × 𝑌)))) | 
| 62 | 47 | adantr 276 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → 𝑅 ∈ Grp) | 
| 63 |   | nnz 9345 | 
. . . . . . . . . . . 12
⊢ (𝑦 ∈ ℕ → 𝑦 ∈
ℤ) | 
| 64 | 63 | adantl 277 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → 𝑦 ∈ ℤ) | 
| 65 | 26 | adantr 276 | 
. . . . . . . . . . 11
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → 𝑋 ∈ 𝐵) | 
| 66 |   | eqid 2196 | 
. . . . . . . . . . . 12
⊢
(invg‘𝑅) = (invg‘𝑅) | 
| 67 | 21, 27, 66 | mulgneg 13270 | 
. . . . . . . . . . 11
⊢ ((𝑅 ∈ Grp ∧ 𝑦 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → (-𝑦 · 𝑋) = ((invg‘𝑅)‘(𝑦 · 𝑋))) | 
| 68 | 62, 64, 65, 67 | syl3anc 1249 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (-𝑦 · 𝑋) = ((invg‘𝑅)‘(𝑦 · 𝑋))) | 
| 69 | 68 | oveq1d 5937 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → ((-𝑦 · 𝑋) × 𝑌) = (((invg‘𝑅)‘(𝑦 · 𝑋)) × 𝑌)) | 
| 70 |   | simpl1 1002 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → 𝑅 ∈ Ring) | 
| 71 | 62, 64, 65, 49 | syl3anc 1249 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (𝑦 · 𝑋) ∈ 𝐵) | 
| 72 |   | simpl2 1003 | 
. . . . . . . . . 10
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → 𝑌 ∈ 𝐵) | 
| 73 | 21, 22, 66, 70, 71, 72 | ringmneg1 13609 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) →
(((invg‘𝑅)‘(𝑦 · 𝑋)) × 𝑌) = ((invg‘𝑅)‘((𝑦 · 𝑋) × 𝑌))) | 
| 74 | 69, 73 | eqtrd 2229 | 
. . . . . . . 8
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → ((-𝑦 · 𝑋) × 𝑌) = ((invg‘𝑅)‘((𝑦 · 𝑋) × 𝑌))) | 
| 75 | 32 | adantr 276 | 
. . . . . . . . 9
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (𝑋 × 𝑌) ∈ 𝐵) | 
| 76 | 21, 27, 66 | mulgneg 13270 | 
. . . . . . . . 9
⊢ ((𝑅 ∈ Grp ∧ 𝑦 ∈ ℤ ∧ (𝑋 × 𝑌) ∈ 𝐵) → (-𝑦 · (𝑋 × 𝑌)) = ((invg‘𝑅)‘(𝑦 · (𝑋 × 𝑌)))) | 
| 77 | 62, 64, 75, 76 | syl3anc 1249 | 
. . . . . . . 8
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (-𝑦 · (𝑋 × 𝑌)) = ((invg‘𝑅)‘(𝑦 · (𝑋 × 𝑌)))) | 
| 78 | 74, 77 | eqeq12d 2211 | 
. . . . . . 7
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (((-𝑦 · 𝑋) × 𝑌) = (-𝑦 · (𝑋 × 𝑌)) ↔ ((invg‘𝑅)‘((𝑦 · 𝑋) × 𝑌)) = ((invg‘𝑅)‘(𝑦 · (𝑋 × 𝑌))))) | 
| 79 | 61, 78 | imbitrrid 156 | 
. . . . . 6
⊢ (((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) ∧ 𝑦 ∈ ℕ) → (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → ((-𝑦 · 𝑋) × 𝑌) = (-𝑦 · (𝑋 × 𝑌)))) | 
| 80 | 79 | ex 115 | 
. . . . 5
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (𝑦 ∈ ℕ → (((𝑦 · 𝑋) × 𝑌) = (𝑦 · (𝑋 × 𝑌)) → ((-𝑦 · 𝑋) × 𝑌) = (-𝑦 · (𝑋 × 𝑌))))) | 
| 81 | 4, 8, 12, 16, 20, 35, 60, 80 | zindd 9444 | 
. . . 4
⊢ ((𝑅 ∈ Ring ∧ 𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵) → (𝑁 ∈ ℤ → ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌)))) | 
| 82 | 81 | 3exp 1204 | 
. . 3
⊢ (𝑅 ∈ Ring → (𝑌 ∈ 𝐵 → (𝑋 ∈ 𝐵 → (𝑁 ∈ ℤ → ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌)))))) | 
| 83 | 82 | com24 87 | 
. 2
⊢ (𝑅 ∈ Ring → (𝑁 ∈ ℤ → (𝑋 ∈ 𝐵 → (𝑌 ∈ 𝐵 → ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌)))))) | 
| 84 | 83 | 3imp2 1224 | 
1
⊢ ((𝑅 ∈ Ring ∧ (𝑁 ∈ ℤ ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵)) → ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌))) |