Proof of Theorem zabsle1
| Step | Hyp | Ref
 | Expression | 
| 1 |   | eltpi 3669 | 
. . 3
⊢ (𝑍 ∈ {-1, 0, 1} → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 2 |   | fveq2 5558 | 
. . . . 5
⊢ (𝑍 = -1 → (abs‘𝑍) =
(abs‘-1)) | 
| 3 |   | ax-1cn 7972 | 
. . . . . . . 8
⊢ 1 ∈
ℂ | 
| 4 | 3 | absnegi 11312 | 
. . . . . . 7
⊢
(abs‘-1) = (abs‘1) | 
| 5 |   | abs1 11237 | 
. . . . . . 7
⊢
(abs‘1) = 1 | 
| 6 | 4, 5 | eqtri 2217 | 
. . . . . 6
⊢
(abs‘-1) = 1 | 
| 7 |   | 1le1 8599 | 
. . . . . 6
⊢ 1 ≤
1 | 
| 8 | 6, 7 | eqbrtri 4054 | 
. . . . 5
⊢
(abs‘-1) ≤ 1 | 
| 9 | 2, 8 | eqbrtrdi 4072 | 
. . . 4
⊢ (𝑍 = -1 → (abs‘𝑍) ≤ 1) | 
| 10 |   | fveq2 5558 | 
. . . . 5
⊢ (𝑍 = 0 → (abs‘𝑍) =
(abs‘0)) | 
| 11 |   | abs0 11223 | 
. . . . . 6
⊢
(abs‘0) = 0 | 
| 12 |   | 0le1 8508 | 
. . . . . 6
⊢ 0 ≤
1 | 
| 13 | 11, 12 | eqbrtri 4054 | 
. . . . 5
⊢
(abs‘0) ≤ 1 | 
| 14 | 10, 13 | eqbrtrdi 4072 | 
. . . 4
⊢ (𝑍 = 0 → (abs‘𝑍) ≤ 1) | 
| 15 |   | fveq2 5558 | 
. . . . 5
⊢ (𝑍 = 1 → (abs‘𝑍) =
(abs‘1)) | 
| 16 | 5, 7 | eqbrtri 4054 | 
. . . . 5
⊢
(abs‘1) ≤ 1 | 
| 17 | 15, 16 | eqbrtrdi 4072 | 
. . . 4
⊢ (𝑍 = 1 → (abs‘𝑍) ≤ 1) | 
| 18 | 9, 14, 17 | 3jaoi 1314 | 
. . 3
⊢ ((𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1) → (abs‘𝑍) ≤ 1) | 
| 19 | 1, 18 | syl 14 | 
. 2
⊢ (𝑍 ∈ {-1, 0, 1} →
(abs‘𝑍) ≤
1) | 
| 20 |   | zre 9330 | 
. . . 4
⊢ (𝑍 ∈ ℤ → 𝑍 ∈
ℝ) | 
| 21 |   | 1red 8041 | 
. . . 4
⊢ (𝑍 ∈ ℤ → 1 ∈
ℝ) | 
| 22 | 20, 21 | absled 11340 | 
. . 3
⊢ (𝑍 ∈ ℤ →
((abs‘𝑍) ≤ 1
↔ (-1 ≤ 𝑍 ∧
𝑍 ≤
1))) | 
| 23 |   | elz 9328 | 
. . . 4
⊢ (𝑍 ∈ ℤ ↔ (𝑍 ∈ ℝ ∧ (𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ))) | 
| 24 |   | 3mix2 1169 | 
. . . . . . . . . 10
⊢ (𝑍 = 0 → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 25 | 24 | a1d 22 | 
. . . . . . . . 9
⊢ (𝑍 = 0 → ((𝑍 ∈ ℝ ∧ (-1 ≤ 𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 26 |   | nnle1eq1 9014 | 
. . . . . . . . . . . . . . 15
⊢ (𝑍 ∈ ℕ → (𝑍 ≤ 1 ↔ 𝑍 = 1)) | 
| 27 | 26 | biimpac 298 | 
. . . . . . . . . . . . . 14
⊢ ((𝑍 ≤ 1 ∧ 𝑍 ∈ ℕ) → 𝑍 = 1) | 
| 28 | 27 | 3mix3d 1176 | 
. . . . . . . . . . . . 13
⊢ ((𝑍 ≤ 1 ∧ 𝑍 ∈ ℕ) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 29 | 28 | ex 115 | 
. . . . . . . . . . . 12
⊢ (𝑍 ≤ 1 → (𝑍 ∈ ℕ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 30 | 29 | adantl 277 | 
. . . . . . . . . . 11
⊢ ((-1 ≤
𝑍 ∧ 𝑍 ≤ 1) → (𝑍 ∈ ℕ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 31 | 30 | adantl 277 | 
. . . . . . . . . 10
⊢ ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 ∈ ℕ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 32 | 31 | com12 30 | 
. . . . . . . . 9
⊢ (𝑍 ∈ ℕ → ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 33 |   | elnnz1 9349 | 
. . . . . . . . . 10
⊢ (-𝑍 ∈ ℕ ↔ (-𝑍 ∈ ℤ ∧ 1 ≤
-𝑍)) | 
| 34 |   | 1red 8041 | 
. . . . . . . . . . . . . . 15
⊢ (𝑍 ∈ ℝ → 1 ∈
ℝ) | 
| 35 |   | lenegcon2 8494 | 
. . . . . . . . . . . . . . 15
⊢ ((1
∈ ℝ ∧ 𝑍
∈ ℝ) → (1 ≤ -𝑍 ↔ 𝑍 ≤ -1)) | 
| 36 | 34, 35 | mpancom 422 | 
. . . . . . . . . . . . . 14
⊢ (𝑍 ∈ ℝ → (1 ≤
-𝑍 ↔ 𝑍 ≤ -1)) | 
| 37 |   | neg1rr 9096 | 
. . . . . . . . . . . . . . . . . . . . 21
⊢ -1 ∈
ℝ | 
| 38 | 37 | a1i 9 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (𝑍 ∈ ℝ → -1 ∈
ℝ) | 
| 39 |   | id 19 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (𝑍 ∈ ℝ → 𝑍 ∈
ℝ) | 
| 40 | 38, 39 | letri3d 8142 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (𝑍 ∈ ℝ → (-1 =
𝑍 ↔ (-1 ≤ 𝑍 ∧ 𝑍 ≤ -1))) | 
| 41 |   | 3mix1 1168 | 
. . . . . . . . . . . . . . . . . . . 20
⊢ (𝑍 = -1 → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 42 | 41 | eqcoms 2199 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (-1 =
𝑍 → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 43 | 40, 42 | biimtrrdi 164 | 
. . . . . . . . . . . . . . . . . 18
⊢ (𝑍 ∈ ℝ → ((-1 ≤
𝑍 ∧ 𝑍 ≤ -1) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 44 | 43 | com12 30 | 
. . . . . . . . . . . . . . . . 17
⊢ ((-1 ≤
𝑍 ∧ 𝑍 ≤ -1) → (𝑍 ∈ ℝ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 45 | 44 | ex 115 | 
. . . . . . . . . . . . . . . 16
⊢ (-1 ≤
𝑍 → (𝑍 ≤ -1 → (𝑍 ∈ ℝ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)))) | 
| 46 | 45 | adantr 276 | 
. . . . . . . . . . . . . . 15
⊢ ((-1 ≤
𝑍 ∧ 𝑍 ≤ 1) → (𝑍 ≤ -1 → (𝑍 ∈ ℝ → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)))) | 
| 47 | 46 | com13 80 | 
. . . . . . . . . . . . . 14
⊢ (𝑍 ∈ ℝ → (𝑍 ≤ -1 → ((-1 ≤ 𝑍 ∧ 𝑍 ≤ 1) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)))) | 
| 48 | 36, 47 | sylbid 150 | 
. . . . . . . . . . . . 13
⊢ (𝑍 ∈ ℝ → (1 ≤
-𝑍 → ((-1 ≤ 𝑍 ∧ 𝑍 ≤ 1) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)))) | 
| 49 | 48 | com12 30 | 
. . . . . . . . . . . 12
⊢ (1 ≤
-𝑍 → (𝑍 ∈ ℝ → ((-1 ≤
𝑍 ∧ 𝑍 ≤ 1) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)))) | 
| 50 | 49 | impd 254 | 
. . . . . . . . . . 11
⊢ (1 ≤
-𝑍 → ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 51 | 50 | adantl 277 | 
. . . . . . . . . 10
⊢ ((-𝑍 ∈ ℤ ∧ 1 ≤
-𝑍) → ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 52 | 33, 51 | sylbi 121 | 
. . . . . . . . 9
⊢ (-𝑍 ∈ ℕ → ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 53 | 25, 32, 52 | 3jaoi 1314 | 
. . . . . . . 8
⊢ ((𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ) → ((𝑍 ∈ ℝ ∧ (-1 ≤ 𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 54 | 53 | imp 124 | 
. . . . . . 7
⊢ (((𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ) ∧ (𝑍 ∈ ℝ ∧ (-1 ≤ 𝑍 ∧ 𝑍 ≤ 1))) → (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1)) | 
| 55 |   | eltpg 3667 | 
. . . . . . . . 9
⊢ (𝑍 ∈ ℝ → (𝑍 ∈ {-1, 0, 1} ↔ (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 56 | 55 | adantr 276 | 
. . . . . . . 8
⊢ ((𝑍 ∈ ℝ ∧ (-1 ≤
𝑍 ∧ 𝑍 ≤ 1)) → (𝑍 ∈ {-1, 0, 1} ↔ (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 57 | 56 | adantl 277 | 
. . . . . . 7
⊢ (((𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ) ∧ (𝑍 ∈ ℝ ∧ (-1 ≤ 𝑍 ∧ 𝑍 ≤ 1))) → (𝑍 ∈ {-1, 0, 1} ↔ (𝑍 = -1 ∨ 𝑍 = 0 ∨ 𝑍 = 1))) | 
| 58 | 54, 57 | mpbird 167 | 
. . . . . 6
⊢ (((𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ) ∧ (𝑍 ∈ ℝ ∧ (-1 ≤ 𝑍 ∧ 𝑍 ≤ 1))) → 𝑍 ∈ {-1, 0, 1}) | 
| 59 | 58 | exp32 365 | 
. . . . 5
⊢ ((𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ) → (𝑍 ∈ ℝ → ((-1 ≤ 𝑍 ∧ 𝑍 ≤ 1) → 𝑍 ∈ {-1, 0, 1}))) | 
| 60 | 59 | impcom 125 | 
. . . 4
⊢ ((𝑍 ∈ ℝ ∧ (𝑍 = 0 ∨ 𝑍 ∈ ℕ ∨ -𝑍 ∈ ℕ)) → ((-1 ≤ 𝑍 ∧ 𝑍 ≤ 1) → 𝑍 ∈ {-1, 0, 1})) | 
| 61 | 23, 60 | sylbi 121 | 
. . 3
⊢ (𝑍 ∈ ℤ → ((-1 ≤
𝑍 ∧ 𝑍 ≤ 1) → 𝑍 ∈ {-1, 0, 1})) | 
| 62 | 22, 61 | sylbid 150 | 
. 2
⊢ (𝑍 ∈ ℤ →
((abs‘𝑍) ≤ 1
→ 𝑍 ∈ {-1, 0,
1})) | 
| 63 | 19, 62 | impbid2 143 | 
1
⊢ (𝑍 ∈ ℤ → (𝑍 ∈ {-1, 0, 1} ↔
(abs‘𝑍) ≤
1)) |