| Step | Hyp | Ref
 | Expression | 
| 1 |   | negeq 8219 | 
. . . . . . 7
⊢ (𝑥 = 0 → -𝑥 = -0) | 
| 2 |   | neg0 8272 | 
. . . . . . 7
⊢ -0 =
0 | 
| 3 | 1, 2 | eqtrdi 2245 | 
. . . . . 6
⊢ (𝑥 = 0 → -𝑥 = 0) | 
| 4 | 3 | oveq1d 5937 | 
. . . . 5
⊢ (𝑥 = 0 → (-𝑥 · 𝑋) = (0 · 𝑋)) | 
| 5 |   | oveq1 5929 | 
. . . . 5
⊢ (𝑥 = 0 → (𝑥 · (𝐼‘𝑋)) = (0 · (𝐼‘𝑋))) | 
| 6 | 4, 5 | eqeq12d 2211 | 
. . . 4
⊢ (𝑥 = 0 → ((-𝑥 · 𝑋) = (𝑥 · (𝐼‘𝑋)) ↔ (0 · 𝑋) = (0 · (𝐼‘𝑋)))) | 
| 7 |   | negeq 8219 | 
. . . . . 6
⊢ (𝑥 = 𝑛 → -𝑥 = -𝑛) | 
| 8 | 7 | oveq1d 5937 | 
. . . . 5
⊢ (𝑥 = 𝑛 → (-𝑥 · 𝑋) = (-𝑛 · 𝑋)) | 
| 9 |   | oveq1 5929 | 
. . . . 5
⊢ (𝑥 = 𝑛 → (𝑥 · (𝐼‘𝑋)) = (𝑛 · (𝐼‘𝑋))) | 
| 10 | 8, 9 | eqeq12d 2211 | 
. . . 4
⊢ (𝑥 = 𝑛 → ((-𝑥 · 𝑋) = (𝑥 · (𝐼‘𝑋)) ↔ (-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)))) | 
| 11 |   | negeq 8219 | 
. . . . . 6
⊢ (𝑥 = (𝑛 + 1) → -𝑥 = -(𝑛 + 1)) | 
| 12 | 11 | oveq1d 5937 | 
. . . . 5
⊢ (𝑥 = (𝑛 + 1) → (-𝑥 · 𝑋) = (-(𝑛 + 1) · 𝑋)) | 
| 13 |   | oveq1 5929 | 
. . . . 5
⊢ (𝑥 = (𝑛 + 1) → (𝑥 · (𝐼‘𝑋)) = ((𝑛 + 1) · (𝐼‘𝑋))) | 
| 14 | 12, 13 | eqeq12d 2211 | 
. . . 4
⊢ (𝑥 = (𝑛 + 1) → ((-𝑥 · 𝑋) = (𝑥 · (𝐼‘𝑋)) ↔ (-(𝑛 + 1) · 𝑋) = ((𝑛 + 1) · (𝐼‘𝑋)))) | 
| 15 |   | negeq 8219 | 
. . . . . 6
⊢ (𝑥 = -𝑛 → -𝑥 = --𝑛) | 
| 16 | 15 | oveq1d 5937 | 
. . . . 5
⊢ (𝑥 = -𝑛 → (-𝑥 · 𝑋) = (--𝑛 · 𝑋)) | 
| 17 |   | oveq1 5929 | 
. . . . 5
⊢ (𝑥 = -𝑛 → (𝑥 · (𝐼‘𝑋)) = (-𝑛 · (𝐼‘𝑋))) | 
| 18 | 16, 17 | eqeq12d 2211 | 
. . . 4
⊢ (𝑥 = -𝑛 → ((-𝑥 · 𝑋) = (𝑥 · (𝐼‘𝑋)) ↔ (--𝑛 · 𝑋) = (-𝑛 · (𝐼‘𝑋)))) | 
| 19 |   | negeq 8219 | 
. . . . . 6
⊢ (𝑥 = 𝑁 → -𝑥 = -𝑁) | 
| 20 | 19 | oveq1d 5937 | 
. . . . 5
⊢ (𝑥 = 𝑁 → (-𝑥 · 𝑋) = (-𝑁 · 𝑋)) | 
| 21 |   | oveq1 5929 | 
. . . . 5
⊢ (𝑥 = 𝑁 → (𝑥 · (𝐼‘𝑋)) = (𝑁 · (𝐼‘𝑋))) | 
| 22 | 20, 21 | eqeq12d 2211 | 
. . . 4
⊢ (𝑥 = 𝑁 → ((-𝑥 · 𝑋) = (𝑥 · (𝐼‘𝑋)) ↔ (-𝑁 · 𝑋) = (𝑁 · (𝐼‘𝑋)))) | 
| 23 |   | mulgneg2.b | 
. . . . . . 7
⊢ 𝐵 = (Base‘𝐺) | 
| 24 |   | eqid 2196 | 
. . . . . . 7
⊢
(0g‘𝐺) = (0g‘𝐺) | 
| 25 |   | mulgneg2.m | 
. . . . . . 7
⊢  · =
(.g‘𝐺) | 
| 26 | 23, 24, 25 | mulg0 13255 | 
. . . . . 6
⊢ (𝑋 ∈ 𝐵 → (0 · 𝑋) = (0g‘𝐺)) | 
| 27 | 26 | adantl 277 | 
. . . . 5
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (0 · 𝑋) = (0g‘𝐺)) | 
| 28 |   | mulgneg2.i | 
. . . . . . 7
⊢ 𝐼 = (invg‘𝐺) | 
| 29 | 23, 28 | grpinvcl 13180 | 
. . . . . 6
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (𝐼‘𝑋) ∈ 𝐵) | 
| 30 | 23, 24, 25 | mulg0 13255 | 
. . . . . 6
⊢ ((𝐼‘𝑋) ∈ 𝐵 → (0 · (𝐼‘𝑋)) = (0g‘𝐺)) | 
| 31 | 29, 30 | syl 14 | 
. . . . 5
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (0 · (𝐼‘𝑋)) = (0g‘𝐺)) | 
| 32 | 27, 31 | eqtr4d 2232 | 
. . . 4
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (0 · 𝑋) = (0 · (𝐼‘𝑋))) | 
| 33 |   | oveq1 5929 | 
. . . . . 6
⊢ ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → ((-𝑛 · 𝑋)(+g‘𝐺)(𝐼‘𝑋)) = ((𝑛 · (𝐼‘𝑋))(+g‘𝐺)(𝐼‘𝑋))) | 
| 34 |   | nn0cn 9259 | 
. . . . . . . . . . 11
⊢ (𝑛 ∈ ℕ0
→ 𝑛 ∈
ℂ) | 
| 35 | 34 | adantl 277 | 
. . . . . . . . . 10
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → 𝑛 ∈
ℂ) | 
| 36 |   | ax-1cn 7972 | 
. . . . . . . . . 10
⊢ 1 ∈
ℂ | 
| 37 |   | negdi 8283 | 
. . . . . . . . . 10
⊢ ((𝑛 ∈ ℂ ∧ 1 ∈
ℂ) → -(𝑛 + 1) =
(-𝑛 + -1)) | 
| 38 | 35, 36, 37 | sylancl 413 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → -(𝑛 + 1) = (-𝑛 + -1)) | 
| 39 | 38 | oveq1d 5937 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → (-(𝑛 + 1) · 𝑋) = ((-𝑛 + -1) · 𝑋)) | 
| 40 |   | simpll 527 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → 𝐺 ∈ Grp) | 
| 41 |   | nn0negz 9360 | 
. . . . . . . . . 10
⊢ (𝑛 ∈ ℕ0
→ -𝑛 ∈
ℤ) | 
| 42 | 41 | adantl 277 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → -𝑛 ∈
ℤ) | 
| 43 |   | 1z 9352 | 
. . . . . . . . . 10
⊢ 1 ∈
ℤ | 
| 44 |   | znegcl 9357 | 
. . . . . . . . . 10
⊢ (1 ∈
ℤ → -1 ∈ ℤ) | 
| 45 | 43, 44 | mp1i 10 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → -1 ∈
ℤ) | 
| 46 |   | simplr 528 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → 𝑋 ∈ 𝐵) | 
| 47 |   | eqid 2196 | 
. . . . . . . . . 10
⊢
(+g‘𝐺) = (+g‘𝐺) | 
| 48 | 23, 25, 47 | mulgdir 13284 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ (-𝑛 ∈ ℤ ∧ -1 ∈
ℤ ∧ 𝑋 ∈
𝐵)) → ((-𝑛 + -1) · 𝑋) = ((-𝑛 · 𝑋)(+g‘𝐺)(-1 · 𝑋))) | 
| 49 | 40, 42, 45, 46, 48 | syl13anc 1251 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → ((-𝑛 + -1) · 𝑋) = ((-𝑛 · 𝑋)(+g‘𝐺)(-1 · 𝑋))) | 
| 50 | 23, 25, 28 | mulgm1 13272 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (-1 · 𝑋) = (𝐼‘𝑋)) | 
| 51 | 50 | adantr 276 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → (-1 · 𝑋) = (𝐼‘𝑋)) | 
| 52 | 51 | oveq2d 5938 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → ((-𝑛 · 𝑋)(+g‘𝐺)(-1 · 𝑋)) = ((-𝑛 · 𝑋)(+g‘𝐺)(𝐼‘𝑋))) | 
| 53 | 39, 49, 52 | 3eqtrd 2233 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → (-(𝑛 + 1) · 𝑋) = ((-𝑛 · 𝑋)(+g‘𝐺)(𝐼‘𝑋))) | 
| 54 |   | grpmnd 13139 | 
. . . . . . . . 9
⊢ (𝐺 ∈ Grp → 𝐺 ∈ Mnd) | 
| 55 | 54 | ad2antrr 488 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → 𝐺 ∈ Mnd) | 
| 56 |   | simpr 110 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → 𝑛 ∈
ℕ0) | 
| 57 | 29 | adantr 276 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → (𝐼‘𝑋) ∈ 𝐵) | 
| 58 | 23, 25, 47 | mulgnn0p1 13263 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Mnd ∧ 𝑛 ∈ ℕ0
∧ (𝐼‘𝑋) ∈ 𝐵) → ((𝑛 + 1) · (𝐼‘𝑋)) = ((𝑛 · (𝐼‘𝑋))(+g‘𝐺)(𝐼‘𝑋))) | 
| 59 | 55, 56, 57, 58 | syl3anc 1249 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → ((𝑛 + 1) · (𝐼‘𝑋)) = ((𝑛 · (𝐼‘𝑋))(+g‘𝐺)(𝐼‘𝑋))) | 
| 60 | 53, 59 | eqeq12d 2211 | 
. . . . . 6
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → ((-(𝑛 + 1) · 𝑋) = ((𝑛 + 1) · (𝐼‘𝑋)) ↔ ((-𝑛 · 𝑋)(+g‘𝐺)(𝐼‘𝑋)) = ((𝑛 · (𝐼‘𝑋))(+g‘𝐺)(𝐼‘𝑋)))) | 
| 61 | 33, 60 | imbitrrid 156 | 
. . . . 5
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ0) → ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → (-(𝑛 + 1) · 𝑋) = ((𝑛 + 1) · (𝐼‘𝑋)))) | 
| 62 | 61 | ex 115 | 
. . . 4
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (𝑛 ∈ ℕ0 → ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → (-(𝑛 + 1) · 𝑋) = ((𝑛 + 1) · (𝐼‘𝑋))))) | 
| 63 |   | fveq2 5558 | 
. . . . . 6
⊢ ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → (𝐼‘(-𝑛 · 𝑋)) = (𝐼‘(𝑛 · (𝐼‘𝑋)))) | 
| 64 |   | simpll 527 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → 𝐺 ∈ Grp) | 
| 65 |   | nnnegz 9329 | 
. . . . . . . . 9
⊢ (𝑛 ∈ ℕ → -𝑛 ∈
ℤ) | 
| 66 | 65 | adantl 277 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → -𝑛 ∈ ℤ) | 
| 67 |   | simplr 528 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → 𝑋 ∈ 𝐵) | 
| 68 | 23, 25, 28 | mulgneg 13270 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Grp ∧ -𝑛 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → (--𝑛 · 𝑋) = (𝐼‘(-𝑛 · 𝑋))) | 
| 69 | 64, 66, 67, 68 | syl3anc 1249 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → (--𝑛 · 𝑋) = (𝐼‘(-𝑛 · 𝑋))) | 
| 70 |   | id 19 | 
. . . . . . . 8
⊢ (𝑛 ∈ ℕ → 𝑛 ∈
ℕ) | 
| 71 | 23, 25, 28 | mulgnegnn 13262 | 
. . . . . . . 8
⊢ ((𝑛 ∈ ℕ ∧ (𝐼‘𝑋) ∈ 𝐵) → (-𝑛 · (𝐼‘𝑋)) = (𝐼‘(𝑛 · (𝐼‘𝑋)))) | 
| 72 | 70, 29, 71 | syl2anr 290 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → (-𝑛 · (𝐼‘𝑋)) = (𝐼‘(𝑛 · (𝐼‘𝑋)))) | 
| 73 | 69, 72 | eqeq12d 2211 | 
. . . . . 6
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → ((--𝑛 · 𝑋) = (-𝑛 · (𝐼‘𝑋)) ↔ (𝐼‘(-𝑛 · 𝑋)) = (𝐼‘(𝑛 · (𝐼‘𝑋))))) | 
| 74 | 63, 73 | imbitrrid 156 | 
. . . . 5
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑛 ∈ ℕ) → ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → (--𝑛 · 𝑋) = (-𝑛 · (𝐼‘𝑋)))) | 
| 75 | 74 | ex 115 | 
. . . 4
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (𝑛 ∈ ℕ → ((-𝑛 · 𝑋) = (𝑛 · (𝐼‘𝑋)) → (--𝑛 · 𝑋) = (-𝑛 · (𝐼‘𝑋))))) | 
| 76 | 6, 10, 14, 18, 22, 32, 62, 75 | zindd 9444 | 
. . 3
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → (𝑁 ∈ ℤ → (-𝑁 · 𝑋) = (𝑁 · (𝐼‘𝑋)))) | 
| 77 | 76 | 3impia 1202 | 
. 2
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵 ∧ 𝑁 ∈ ℤ) → (-𝑁 · 𝑋) = (𝑁 · (𝐼‘𝑋))) | 
| 78 | 77 | 3com23 1211 | 
1
⊢ ((𝐺 ∈ Grp ∧ 𝑁 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → (-𝑁 · 𝑋) = (𝑁 · (𝐼‘𝑋))) |