| Step | Hyp | Ref
 | Expression | 
| 1 |   | oveq2 5930 | 
. . . . . . . . 9
⊢ (𝑥 = 𝑁 → (𝐴 /L 𝑥) = (𝐴 /L 𝑁)) | 
| 2 | 1 | oveq1d 5937 | 
. . . . . . . 8
⊢ (𝑥 = 𝑁 → ((𝐴 /L 𝑥) · (𝐴 /L 0)) = ((𝐴 /L 𝑁) · (𝐴 /L 0))) | 
| 3 | 2 | eqeq2d 2208 | 
. . . . . . 7
⊢ (𝑥 = 𝑁 → ((𝐴 /L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0)) ↔ (𝐴 /L 0) =
((𝐴 /L
𝑁) · (𝐴 /L
0)))) | 
| 4 |   | sq1 10725 | 
. . . . . . . . . . . . . . . . 17
⊢
(1↑2) = 1 | 
| 5 | 4 | eqeq2i 2207 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝐴↑2) = (1↑2) ↔
(𝐴↑2) =
1) | 
| 6 |   | nn0re 9258 | 
. . . . . . . . . . . . . . . . . 18
⊢ (𝐴 ∈ ℕ0
→ 𝐴 ∈
ℝ) | 
| 7 |   | nn0ge0 9274 | 
. . . . . . . . . . . . . . . . . 18
⊢ (𝐴 ∈ ℕ0
→ 0 ≤ 𝐴) | 
| 8 |   | 1re 8025 | 
. . . . . . . . . . . . . . . . . . 19
⊢ 1 ∈
ℝ | 
| 9 |   | 0le1 8508 | 
. . . . . . . . . . . . . . . . . . 19
⊢ 0 ≤
1 | 
| 10 |   | sq11 10704 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (((𝐴 ∈ ℝ ∧ 0 ≤
𝐴) ∧ (1 ∈ ℝ
∧ 0 ≤ 1)) → ((𝐴↑2) = (1↑2) ↔ 𝐴 = 1)) | 
| 11 | 8, 9, 10 | mpanr12 439 | 
. . . . . . . . . . . . . . . . . 18
⊢ ((𝐴 ∈ ℝ ∧ 0 ≤
𝐴) → ((𝐴↑2) = (1↑2) ↔
𝐴 = 1)) | 
| 12 | 6, 7, 11 | syl2anc 411 | 
. . . . . . . . . . . . . . . . 17
⊢ (𝐴 ∈ ℕ0
→ ((𝐴↑2) =
(1↑2) ↔ 𝐴 =
1)) | 
| 13 | 12 | adantr 276 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ ((𝐴↑2) =
(1↑2) ↔ 𝐴 =
1)) | 
| 14 | 5, 13 | bitr3id 194 | 
. . . . . . . . . . . . . . 15
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ ((𝐴↑2) = 1
↔ 𝐴 =
1)) | 
| 15 | 14 | biimpa 296 | 
. . . . . . . . . . . . . 14
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ 𝐴 =
1) | 
| 16 | 15 | oveq1d 5937 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (𝐴
/L 𝑥) =
(1 /L 𝑥)) | 
| 17 |   | 1lgs 15284 | 
. . . . . . . . . . . . . 14
⊢ (𝑥 ∈ ℤ → (1
/L 𝑥) =
1) | 
| 18 | 17 | ad2antlr 489 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (1 /L 𝑥) = 1) | 
| 19 | 16, 18 | eqtrd 2229 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (𝐴
/L 𝑥) =
1) | 
| 20 | 19 | oveq1d 5937 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ ((𝐴
/L 𝑥)
· (𝐴
/L 0)) = (1 · (𝐴 /L 0))) | 
| 21 |   | nn0z 9346 | 
. . . . . . . . . . . . . . 15
⊢ (𝐴 ∈ ℕ0
→ 𝐴 ∈
ℤ) | 
| 22 | 21 | ad2antrr 488 | 
. . . . . . . . . . . . . 14
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ 𝐴 ∈
ℤ) | 
| 23 |   | 0z 9337 | 
. . . . . . . . . . . . . 14
⊢ 0 ∈
ℤ | 
| 24 |   | lgscl 15255 | 
. . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℤ ∧ 0 ∈
ℤ) → (𝐴
/L 0) ∈ ℤ) | 
| 25 | 22, 23, 24 | sylancl 413 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (𝐴
/L 0) ∈ ℤ) | 
| 26 | 25 | zcnd 9449 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (𝐴
/L 0) ∈ ℂ) | 
| 27 | 26 | mulid2d 8045 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (1 · (𝐴
/L 0)) = (𝐴 /L 0)) | 
| 28 | 20, 27 | eqtr2d 2230 | 
. . . . . . . . . 10
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) = 1)
→ (𝐴
/L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0))) | 
| 29 |   | lgscl 15255 | 
. . . . . . . . . . . . . . 15
⊢ ((𝐴 ∈ ℤ ∧ 𝑥 ∈ ℤ) → (𝐴 /L 𝑥) ∈
ℤ) | 
| 30 | 21, 29 | sylan 283 | 
. . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ (𝐴
/L 𝑥)
∈ ℤ) | 
| 31 | 30 | zcnd 9449 | 
. . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ (𝐴
/L 𝑥)
∈ ℂ) | 
| 32 | 31 | adantr 276 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) ≠ 1)
→ (𝐴
/L 𝑥)
∈ ℂ) | 
| 33 | 32 | mul01d 8419 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) ≠ 1)
→ ((𝐴
/L 𝑥)
· 0) = 0) | 
| 34 | 21 | adantr 276 | 
. . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ 𝐴 ∈
ℤ) | 
| 35 |   | lgs0 15254 | 
. . . . . . . . . . . . . 14
⊢ (𝐴 ∈ ℤ → (𝐴 /L 0) =
if((𝐴↑2) = 1, 1,
0)) | 
| 36 | 34, 35 | syl 14 | 
. . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ (𝐴
/L 0) = if((𝐴↑2) = 1, 1, 0)) | 
| 37 |   | ifnefalse 3572 | 
. . . . . . . . . . . . 13
⊢ ((𝐴↑2) ≠ 1 → if((𝐴↑2) = 1, 1, 0) =
0) | 
| 38 | 36, 37 | sylan9eq 2249 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) ≠ 1)
→ (𝐴
/L 0) = 0) | 
| 39 | 38 | oveq2d 5938 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) ≠ 1)
→ ((𝐴
/L 𝑥)
· (𝐴
/L 0)) = ((𝐴 /L 𝑥) · 0)) | 
| 40 | 33, 39, 38 | 3eqtr4rd 2240 | 
. . . . . . . . . 10
⊢ (((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
∧ (𝐴↑2) ≠ 1)
→ (𝐴
/L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0))) | 
| 41 |   | zsqcl 10702 | 
. . . . . . . . . . . . 13
⊢ (𝐴 ∈ ℤ → (𝐴↑2) ∈
ℤ) | 
| 42 | 34, 41 | syl 14 | 
. . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ (𝐴↑2) ∈
ℤ) | 
| 43 |   | 1z 9352 | 
. . . . . . . . . . . 12
⊢ 1 ∈
ℤ | 
| 44 |   | zdceq 9401 | 
. . . . . . . . . . . 12
⊢ (((𝐴↑2) ∈ ℤ ∧ 1
∈ ℤ) → DECID (𝐴↑2) = 1) | 
| 45 | 42, 43, 44 | sylancl 413 | 
. . . . . . . . . . 11
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ DECID (𝐴↑2) = 1) | 
| 46 |   | dcne 2378 | 
. . . . . . . . . . 11
⊢
(DECID (𝐴↑2) = 1 ↔ ((𝐴↑2) = 1 ∨ (𝐴↑2) ≠ 1)) | 
| 47 | 45, 46 | sylib 122 | 
. . . . . . . . . 10
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ ((𝐴↑2) = 1 ∨
(𝐴↑2) ≠
1)) | 
| 48 | 28, 40, 47 | mpjaodan 799 | 
. . . . . . . . 9
⊢ ((𝐴 ∈ ℕ0
∧ 𝑥 ∈ ℤ)
→ (𝐴
/L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0))) | 
| 49 | 48 | ralrimiva 2570 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℕ0
→ ∀𝑥 ∈
ℤ (𝐴
/L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0))) | 
| 50 | 49 | 3ad2ant1 1020 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ ∀𝑥 ∈
ℤ (𝐴
/L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0))) | 
| 51 |   | simp3 1001 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ 𝑁 ∈
ℤ) | 
| 52 | 3, 50, 51 | rspcdva 2873 | 
. . . . . 6
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 0) = ((𝐴 /L 𝑁) · (𝐴 /L 0))) | 
| 53 | 52 | adantr 276 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L 0) =
((𝐴 /L
𝑁) · (𝐴 /L
0))) | 
| 54 | 21 | 3ad2ant1 1020 | 
. . . . . . . . 9
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ 𝐴 ∈
ℤ) | 
| 55 | 54, 23, 24 | sylancl 413 | 
. . . . . . . 8
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 0) ∈ ℤ) | 
| 56 | 55 | zcnd 9449 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 0) ∈ ℂ) | 
| 57 | 56 | adantr 276 | 
. . . . . 6
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L 0) ∈
ℂ) | 
| 58 |   | lgscl 15255 | 
. . . . . . . . 9
⊢ ((𝐴 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝐴 /L 𝑁) ∈
ℤ) | 
| 59 | 54, 51, 58 | syl2anc 411 | 
. . . . . . . 8
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 𝑁)
∈ ℤ) | 
| 60 | 59 | zcnd 9449 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 𝑁)
∈ ℂ) | 
| 61 | 60 | adantr 276 | 
. . . . . 6
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L 𝑁) ∈
ℂ) | 
| 62 | 57, 61 | mulcomd 8048 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → ((𝐴 /L 0)
· (𝐴
/L 𝑁)) =
((𝐴 /L
𝑁) · (𝐴 /L
0))) | 
| 63 | 53, 62 | eqtr4d 2232 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L 0) =
((𝐴 /L 0)
· (𝐴
/L 𝑁))) | 
| 64 |   | oveq1 5929 | 
. . . . . 6
⊢ (𝑀 = 0 → (𝑀 · 𝑁) = (0 · 𝑁)) | 
| 65 | 51 | zcnd 9449 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ 𝑁 ∈
ℂ) | 
| 66 | 65 | mul02d 8418 | 
. . . . . 6
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (0 · 𝑁) =
0) | 
| 67 | 64, 66 | sylan9eqr 2251 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝑀 · 𝑁) = 0) | 
| 68 | 67 | oveq2d 5938 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L (𝑀 · 𝑁)) = (𝐴 /L 0)) | 
| 69 |   | simpr 110 | 
. . . . . 6
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → 𝑀 = 0) | 
| 70 | 69 | oveq2d 5938 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L 𝑀) = (𝐴 /L 0)) | 
| 71 | 70 | oveq1d 5937 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → ((𝐴 /L 𝑀) · (𝐴 /L 𝑁)) = ((𝐴 /L 0) · (𝐴 /L 𝑁))) | 
| 72 | 63, 68, 71 | 3eqtr4d 2239 | 
. . 3
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑀 = 0) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 73 |   | oveq2 5930 | 
. . . . . . . 8
⊢ (𝑥 = 𝑀 → (𝐴 /L 𝑥) = (𝐴 /L 𝑀)) | 
| 74 | 73 | oveq1d 5937 | 
. . . . . . 7
⊢ (𝑥 = 𝑀 → ((𝐴 /L 𝑥) · (𝐴 /L 0)) = ((𝐴 /L 𝑀) · (𝐴 /L 0))) | 
| 75 | 74 | eqeq2d 2208 | 
. . . . . 6
⊢ (𝑥 = 𝑀 → ((𝐴 /L 0) = ((𝐴 /L 𝑥) · (𝐴 /L 0)) ↔ (𝐴 /L 0) =
((𝐴 /L
𝑀) · (𝐴 /L
0)))) | 
| 76 |   | simp2 1000 | 
. . . . . 6
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ 𝑀 ∈
ℤ) | 
| 77 | 75, 50, 76 | rspcdva 2873 | 
. . . . 5
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L 0) = ((𝐴 /L 𝑀) · (𝐴 /L 0))) | 
| 78 | 77 | adantr 276 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → (𝐴 /L 0) =
((𝐴 /L
𝑀) · (𝐴 /L
0))) | 
| 79 |   | oveq2 5930 | 
. . . . . 6
⊢ (𝑁 = 0 → (𝑀 · 𝑁) = (𝑀 · 0)) | 
| 80 | 76 | zcnd 9449 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ 𝑀 ∈
ℂ) | 
| 81 | 80 | mul01d 8419 | 
. . . . . 6
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝑀 · 0) =
0) | 
| 82 | 79, 81 | sylan9eqr 2251 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → (𝑀 · 𝑁) = 0) | 
| 83 | 82 | oveq2d 5938 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → (𝐴 /L (𝑀 · 𝑁)) = (𝐴 /L 0)) | 
| 84 |   | simpr 110 | 
. . . . . 6
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → 𝑁 = 0) | 
| 85 | 84 | oveq2d 5938 | 
. . . . 5
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → (𝐴 /L 𝑁) = (𝐴 /L 0)) | 
| 86 | 85 | oveq2d 5938 | 
. . . 4
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → ((𝐴 /L 𝑀) · (𝐴 /L 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 0))) | 
| 87 | 78, 83, 86 | 3eqtr4d 2239 | 
. . 3
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ 𝑁 = 0) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 88 | 72, 87 | jaodan 798 | 
. 2
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ (𝑀 = 0 ∨ 𝑁 = 0)) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 89 |   | neanior 2454 | 
. . 3
⊢ ((𝑀 ≠ 0 ∧ 𝑁 ≠ 0) ↔ ¬ (𝑀 = 0 ∨ 𝑁 = 0)) | 
| 90 |   | lgsdi 15278 | 
. . . 4
⊢ (((𝐴 ∈ ℤ ∧ 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 ≠ 0 ∧ 𝑁 ≠ 0)) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 91 | 21, 90 | syl3anl1 1297 | 
. . 3
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ (𝑀 ≠ 0 ∧ 𝑁 ≠ 0)) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 92 | 89, 91 | sylan2br 288 | 
. 2
⊢ (((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
∧ ¬ (𝑀 = 0 ∨
𝑁 = 0)) → (𝐴 /L (𝑀 · 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) | 
| 93 |   | zdceq 9401 | 
. . . . 5
⊢ ((𝑀 ∈ ℤ ∧ 0 ∈
ℤ) → DECID 𝑀 = 0) | 
| 94 | 76, 23, 93 | sylancl 413 | 
. . . 4
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ DECID 𝑀 = 0) | 
| 95 |   | zdceq 9401 | 
. . . . 5
⊢ ((𝑁 ∈ ℤ ∧ 0 ∈
ℤ) → DECID 𝑁 = 0) | 
| 96 | 51, 23, 95 | sylancl 413 | 
. . . 4
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ DECID 𝑁 = 0) | 
| 97 |   | dcor 937 | 
. . . 4
⊢
(DECID 𝑀 = 0 → (DECID 𝑁 = 0 → DECID
(𝑀 = 0 ∨ 𝑁 = 0))) | 
| 98 | 94, 96, 97 | sylc 62 | 
. . 3
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ DECID (𝑀 = 0 ∨ 𝑁 = 0)) | 
| 99 |   | exmiddc 837 | 
. . 3
⊢
(DECID (𝑀 = 0 ∨ 𝑁 = 0) → ((𝑀 = 0 ∨ 𝑁 = 0) ∨ ¬ (𝑀 = 0 ∨ 𝑁 = 0))) | 
| 100 | 98, 99 | syl 14 | 
. 2
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ ((𝑀 = 0 ∨ 𝑁 = 0) ∨ ¬ (𝑀 = 0 ∨ 𝑁 = 0))) | 
| 101 | 88, 92, 100 | mpjaodan 799 | 
1
⊢ ((𝐴 ∈ ℕ0
∧ 𝑀 ∈ ℤ
∧ 𝑁 ∈ ℤ)
→ (𝐴
/L (𝑀
· 𝑁)) = ((𝐴 /L 𝑀) · (𝐴 /L 𝑁))) |