| Step | Hyp | Ref
| Expression |
| 1 | | df-lcm 10443 |
. . 3
⊢ lcm =
(𝑥 ∈ ℤ, 𝑦 ∈ ℤ ↦
if((𝑥 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < ))) |
| 2 | 1 | a1i 9 |
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → lcm =
(𝑥 ∈ ℤ, 𝑦 ∈ ℤ ↦
if((𝑥 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )))) |
| 3 | | eqeq1 2087 |
. . . . . 6
⊢ (𝑥 = 𝑀 → (𝑥 = 0 ↔ 𝑀 = 0)) |
| 4 | 3 | orbi1d 737 |
. . . . 5
⊢ (𝑥 = 𝑀 → ((𝑥 = 0 ∨ 𝑦 = 0) ↔ (𝑀 = 0 ∨ 𝑦 = 0))) |
| 5 | | breq1 3788 |
. . . . . . . 8
⊢ (𝑥 = 𝑀 → (𝑥 ∥ 𝑛 ↔ 𝑀 ∥ 𝑛)) |
| 6 | 5 | anbi1d 452 |
. . . . . . 7
⊢ (𝑥 = 𝑀 → ((𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛) ↔ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛))) |
| 7 | 6 | rabbidv 2593 |
. . . . . 6
⊢ (𝑥 = 𝑀 → {𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)} = {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}) |
| 8 | 7 | infeq1d 6425 |
. . . . 5
⊢ (𝑥 = 𝑀 → inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < ) = inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )) |
| 9 | 4, 8 | ifbieq2d 3373 |
. . . 4
⊢ (𝑥 = 𝑀 → if((𝑥 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )) = if((𝑀 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < ))) |
| 10 | | eqeq1 2087 |
. . . . . 6
⊢ (𝑦 = 𝑁 → (𝑦 = 0 ↔ 𝑁 = 0)) |
| 11 | 10 | orbi2d 736 |
. . . . 5
⊢ (𝑦 = 𝑁 → ((𝑀 = 0 ∨ 𝑦 = 0) ↔ (𝑀 = 0 ∨ 𝑁 = 0))) |
| 12 | | breq1 3788 |
. . . . . . . 8
⊢ (𝑦 = 𝑁 → (𝑦 ∥ 𝑛 ↔ 𝑁 ∥ 𝑛)) |
| 13 | 12 | anbi2d 451 |
. . . . . . 7
⊢ (𝑦 = 𝑁 → ((𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛) ↔ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛))) |
| 14 | 13 | rabbidv 2593 |
. . . . . 6
⊢ (𝑦 = 𝑁 → {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)} = {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}) |
| 15 | 14 | infeq1d 6425 |
. . . . 5
⊢ (𝑦 = 𝑁 → inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < ) = inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < )) |
| 16 | 11, 15 | ifbieq2d 3373 |
. . . 4
⊢ (𝑦 = 𝑁 → if((𝑀 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )) = if((𝑀 = 0 ∨ 𝑁 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ))) |
| 17 | 9, 16 | sylan9eq 2133 |
. . 3
⊢ ((𝑥 = 𝑀 ∧ 𝑦 = 𝑁) → if((𝑥 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )) = if((𝑀 = 0 ∨ 𝑁 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ))) |
| 18 | 17 | adantl 271 |
. 2
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑥 = 𝑀 ∧ 𝑦 = 𝑁)) → if((𝑥 = 0 ∨ 𝑦 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑥 ∥ 𝑛 ∧ 𝑦 ∥ 𝑛)}, ℝ, < )) = if((𝑀 = 0 ∨ 𝑁 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ))) |
| 19 | | simpl 107 |
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑀 ∈
ℤ) |
| 20 | | simpr 108 |
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑁 ∈
ℤ) |
| 21 | | c0ex 7113 |
. . . 4
⊢ 0 ∈
V |
| 22 | 21 | a1i 9 |
. . 3
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ (𝑀 = 0 ∨ 𝑁 = 0)) → 0 ∈ V) |
| 23 | | 1zzd 8378 |
. . . . 5
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 1 ∈
ℤ) |
| 24 | | nnuz 8654 |
. . . . . 6
⊢ ℕ =
(ℤ≥‘1) |
| 25 | | rabeq 2595 |
. . . . . 6
⊢ (ℕ
= (ℤ≥‘1) → {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)} = {𝑛 ∈ (ℤ≥‘1)
∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}) |
| 26 | 24, 25 | ax-mp 7 |
. . . . 5
⊢ {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)} = {𝑛 ∈ (ℤ≥‘1)
∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)} |
| 27 | | dvdsmul1 10217 |
. . . . . . . 8
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑀 ∥ (𝑀 · 𝑁)) |
| 28 | 27 | adantr 270 |
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑀 ∥ (𝑀 · 𝑁)) |
| 29 | | simpll 495 |
. . . . . . . 8
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑀 ∈ ℤ) |
| 30 | | simplr 496 |
. . . . . . . . 9
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑁 ∈ ℤ) |
| 31 | 29, 30 | zmulcld 8475 |
. . . . . . . 8
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (𝑀 · 𝑁) ∈ ℤ) |
| 32 | | dvdsabsb 10214 |
. . . . . . . 8
⊢ ((𝑀 ∈ ℤ ∧ (𝑀 · 𝑁) ∈ ℤ) → (𝑀 ∥ (𝑀 · 𝑁) ↔ 𝑀 ∥ (abs‘(𝑀 · 𝑁)))) |
| 33 | 29, 31, 32 | syl2anc 403 |
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (𝑀 ∥ (𝑀 · 𝑁) ↔ 𝑀 ∥ (abs‘(𝑀 · 𝑁)))) |
| 34 | 28, 33 | mpbid 145 |
. . . . . 6
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑀 ∥ (abs‘(𝑀 · 𝑁))) |
| 35 | | dvdsmul2 10218 |
. . . . . . . 8
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → 𝑁 ∥ (𝑀 · 𝑁)) |
| 36 | 35 | adantr 270 |
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑁 ∥ (𝑀 · 𝑁)) |
| 37 | | dvdsabsb 10214 |
. . . . . . . 8
⊢ ((𝑁 ∈ ℤ ∧ (𝑀 · 𝑁) ∈ ℤ) → (𝑁 ∥ (𝑀 · 𝑁) ↔ 𝑁 ∥ (abs‘(𝑀 · 𝑁)))) |
| 38 | 30, 31, 37 | syl2anc 403 |
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (𝑁 ∥ (𝑀 · 𝑁) ↔ 𝑁 ∥ (abs‘(𝑀 · 𝑁)))) |
| 39 | 36, 38 | mpbid 145 |
. . . . . 6
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑁 ∥ (abs‘(𝑀 · 𝑁))) |
| 40 | 29 | zcnd 8470 |
. . . . . . . . 9
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑀 ∈ ℂ) |
| 41 | 30 | zcnd 8470 |
. . . . . . . . 9
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑁 ∈ ℂ) |
| 42 | 40, 41 | absmuld 10080 |
. . . . . . . 8
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (abs‘(𝑀 · 𝑁)) = ((abs‘𝑀) · (abs‘𝑁))) |
| 43 | | simpr 108 |
. . . . . . . . . . . . 13
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → ¬ (𝑀 = 0 ∨ 𝑁 = 0)) |
| 44 | | ioran 701 |
. . . . . . . . . . . . 13
⊢ (¬
(𝑀 = 0 ∨ 𝑁 = 0) ↔ (¬ 𝑀 = 0 ∧ ¬ 𝑁 = 0)) |
| 45 | 43, 44 | sylib 120 |
. . . . . . . . . . . 12
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (¬ 𝑀 = 0 ∧ ¬ 𝑁 = 0)) |
| 46 | 45 | simpld 110 |
. . . . . . . . . . 11
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → ¬ 𝑀 = 0) |
| 47 | 46 | neqned 2252 |
. . . . . . . . . 10
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑀 ≠ 0) |
| 48 | | nnabscl 9986 |
. . . . . . . . . 10
⊢ ((𝑀 ∈ ℤ ∧ 𝑀 ≠ 0) → (abs‘𝑀) ∈
ℕ) |
| 49 | 29, 47, 48 | syl2anc 403 |
. . . . . . . . 9
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (abs‘𝑀) ∈
ℕ) |
| 50 | 45 | simprd 112 |
. . . . . . . . . . 11
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → ¬ 𝑁 = 0) |
| 51 | 50 | neqned 2252 |
. . . . . . . . . 10
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → 𝑁 ≠ 0) |
| 52 | | nnabscl 9986 |
. . . . . . . . . 10
⊢ ((𝑁 ∈ ℤ ∧ 𝑁 ≠ 0) → (abs‘𝑁) ∈
ℕ) |
| 53 | 30, 51, 52 | syl2anc 403 |
. . . . . . . . 9
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (abs‘𝑁) ∈
ℕ) |
| 54 | 49, 53 | nnmulcld 8087 |
. . . . . . . 8
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → ((abs‘𝑀) · (abs‘𝑁)) ∈
ℕ) |
| 55 | 42, 54 | eqeltrd 2155 |
. . . . . . 7
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (abs‘(𝑀 · 𝑁)) ∈ ℕ) |
| 56 | | breq2 3789 |
. . . . . . . . 9
⊢ (𝑛 = (abs‘(𝑀 · 𝑁)) → (𝑀 ∥ 𝑛 ↔ 𝑀 ∥ (abs‘(𝑀 · 𝑁)))) |
| 57 | | breq2 3789 |
. . . . . . . . 9
⊢ (𝑛 = (abs‘(𝑀 · 𝑁)) → (𝑁 ∥ 𝑛 ↔ 𝑁 ∥ (abs‘(𝑀 · 𝑁)))) |
| 58 | 56, 57 | anbi12d 456 |
. . . . . . . 8
⊢ (𝑛 = (abs‘(𝑀 · 𝑁)) → ((𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛) ↔ (𝑀 ∥ (abs‘(𝑀 · 𝑁)) ∧ 𝑁 ∥ (abs‘(𝑀 · 𝑁))))) |
| 59 | 58 | elrab3 2750 |
. . . . . . 7
⊢
((abs‘(𝑀
· 𝑁)) ∈ ℕ
→ ((abs‘(𝑀
· 𝑁)) ∈ {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)} ↔ (𝑀 ∥ (abs‘(𝑀 · 𝑁)) ∧ 𝑁 ∥ (abs‘(𝑀 · 𝑁))))) |
| 60 | 55, 59 | syl 14 |
. . . . . 6
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → ((abs‘(𝑀 · 𝑁)) ∈ {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)} ↔ (𝑀 ∥ (abs‘(𝑀 · 𝑁)) ∧ 𝑁 ∥ (abs‘(𝑀 · 𝑁))))) |
| 61 | 34, 39, 60 | mpbir2and 885 |
. . . . 5
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → (abs‘(𝑀 · 𝑁)) ∈ {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}) |
| 62 | | elfzelz 9045 |
. . . . . . 7
⊢ (𝑛 ∈ (1...(abs‘(𝑀 · 𝑁))) → 𝑛 ∈ ℤ) |
| 63 | | zdvdsdc 10216 |
. . . . . . 7
⊢ ((𝑀 ∈ ℤ ∧ 𝑛 ∈ ℤ) →
DECID 𝑀
∥ 𝑛) |
| 64 | 29, 62, 63 | syl2an 283 |
. . . . . 6
⊢ ((((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) ∧ 𝑛 ∈ (1...(abs‘(𝑀 · 𝑁)))) → DECID 𝑀 ∥ 𝑛) |
| 65 | | zdvdsdc 10216 |
. . . . . . 7
⊢ ((𝑁 ∈ ℤ ∧ 𝑛 ∈ ℤ) →
DECID 𝑁
∥ 𝑛) |
| 66 | 30, 62, 65 | syl2an 283 |
. . . . . 6
⊢ ((((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) ∧ 𝑛 ∈ (1...(abs‘(𝑀 · 𝑁)))) → DECID 𝑁 ∥ 𝑛) |
| 67 | | dcan 875 |
. . . . . 6
⊢
(DECID 𝑀 ∥ 𝑛 → (DECID 𝑁 ∥ 𝑛 → DECID (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛))) |
| 68 | 64, 66, 67 | sylc 61 |
. . . . 5
⊢ ((((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) ∧ 𝑛 ∈ (1...(abs‘(𝑀 · 𝑁)))) → DECID (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)) |
| 69 | 23, 26, 61, 68 | infssuzcldc 10347 |
. . . 4
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ) ∈ {𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}) |
| 70 | 69 | elexd 2612 |
. . 3
⊢ (((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) ∧ ¬
(𝑀 = 0 ∨ 𝑁 = 0)) → inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ) ∈
V) |
| 71 | | lcmmndc 10444 |
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) →
DECID (𝑀 = 0
∨ 𝑁 =
0)) |
| 72 | 22, 70, 71 | ifcldadc 3378 |
. 2
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) →
if((𝑀 = 0 ∨ 𝑁 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < )) ∈
V) |
| 73 | 2, 18, 19, 20, 72 | ovmpt2d 5648 |
1
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ) → (𝑀 lcm 𝑁) = if((𝑀 = 0 ∨ 𝑁 = 0), 0, inf({𝑛 ∈ ℕ ∣ (𝑀 ∥ 𝑛 ∧ 𝑁 ∥ 𝑛)}, ℝ, < ))) |