Proof of Theorem xrltnr
| Step | Hyp | Ref
 | Expression | 
| 1 |   | elxr 9851 | 
. 2
⊢ (𝐴 ∈ ℝ*
↔ (𝐴 ∈ ℝ
∨ 𝐴 = +∞ ∨
𝐴 =
-∞)) | 
| 2 |   | ltnr 8103 | 
. . 3
⊢ (𝐴 ∈ ℝ → ¬
𝐴 < 𝐴) | 
| 3 |   | pnfnre 8068 | 
. . . . . . . . . 10
⊢ +∞
∉ ℝ | 
| 4 | 3 | neli 2464 | 
. . . . . . . . 9
⊢  ¬
+∞ ∈ ℝ | 
| 5 | 4 | intnan 930 | 
. . . . . . . 8
⊢  ¬
(+∞ ∈ ℝ ∧ +∞ ∈ ℝ) | 
| 6 | 5 | intnanr 931 | 
. . . . . . 7
⊢  ¬
((+∞ ∈ ℝ ∧ +∞ ∈ ℝ) ∧ +∞
<ℝ +∞) | 
| 7 |   | pnfnemnf 8081 | 
. . . . . . . . 9
⊢ +∞
≠ -∞ | 
| 8 | 7 | neii 2369 | 
. . . . . . . 8
⊢  ¬
+∞ = -∞ | 
| 9 | 8 | intnanr 931 | 
. . . . . . 7
⊢  ¬
(+∞ = -∞ ∧ +∞ = +∞) | 
| 10 | 6, 9 | pm3.2ni 814 | 
. . . . . 6
⊢  ¬
(((+∞ ∈ ℝ ∧ +∞ ∈ ℝ) ∧ +∞
<ℝ +∞) ∨ (+∞ = -∞ ∧ +∞ =
+∞)) | 
| 11 | 4 | intnanr 931 | 
. . . . . . 7
⊢  ¬
(+∞ ∈ ℝ ∧ +∞ = +∞) | 
| 12 | 4 | intnan 930 | 
. . . . . . 7
⊢  ¬
(+∞ = -∞ ∧ +∞ ∈ ℝ) | 
| 13 | 11, 12 | pm3.2ni 814 | 
. . . . . 6
⊢  ¬
((+∞ ∈ ℝ ∧ +∞ = +∞) ∨ (+∞ = -∞
∧ +∞ ∈ ℝ)) | 
| 14 | 10, 13 | pm3.2ni 814 | 
. . . . 5
⊢  ¬
((((+∞ ∈ ℝ ∧ +∞ ∈ ℝ) ∧ +∞
<ℝ +∞) ∨ (+∞ = -∞ ∧ +∞ =
+∞)) ∨ ((+∞ ∈ ℝ ∧ +∞ = +∞) ∨
(+∞ = -∞ ∧ +∞ ∈ ℝ))) | 
| 15 |   | pnfxr 8079 | 
. . . . . 6
⊢ +∞
∈ ℝ* | 
| 16 |   | ltxr 9850 | 
. . . . . 6
⊢
((+∞ ∈ ℝ* ∧ +∞ ∈
ℝ*) → (+∞ < +∞ ↔ ((((+∞ ∈
ℝ ∧ +∞ ∈ ℝ) ∧ +∞ <ℝ
+∞) ∨ (+∞ = -∞ ∧ +∞ = +∞)) ∨ ((+∞
∈ ℝ ∧ +∞ = +∞) ∨ (+∞ = -∞ ∧
+∞ ∈ ℝ))))) | 
| 17 | 15, 15, 16 | mp2an 426 | 
. . . . 5
⊢ (+∞
< +∞ ↔ ((((+∞ ∈ ℝ ∧ +∞ ∈ ℝ)
∧ +∞ <ℝ +∞) ∨ (+∞ = -∞ ∧
+∞ = +∞)) ∨ ((+∞ ∈ ℝ ∧ +∞ = +∞)
∨ (+∞ = -∞ ∧ +∞ ∈ ℝ)))) | 
| 18 | 14, 17 | mtbir 672 | 
. . . 4
⊢  ¬
+∞ < +∞ | 
| 19 |   | breq12 4038 | 
. . . . 5
⊢ ((𝐴 = +∞ ∧ 𝐴 = +∞) → (𝐴 < 𝐴 ↔ +∞ <
+∞)) | 
| 20 | 19 | anidms 397 | 
. . . 4
⊢ (𝐴 = +∞ → (𝐴 < 𝐴 ↔ +∞ <
+∞)) | 
| 21 | 18, 20 | mtbiri 676 | 
. . 3
⊢ (𝐴 = +∞ → ¬ 𝐴 < 𝐴) | 
| 22 |   | mnfnre 8069 | 
. . . . . . . . . 10
⊢ -∞
∉ ℝ | 
| 23 | 22 | neli 2464 | 
. . . . . . . . 9
⊢  ¬
-∞ ∈ ℝ | 
| 24 | 23 | intnan 930 | 
. . . . . . . 8
⊢  ¬
(-∞ ∈ ℝ ∧ -∞ ∈ ℝ) | 
| 25 | 24 | intnanr 931 | 
. . . . . . 7
⊢  ¬
((-∞ ∈ ℝ ∧ -∞ ∈ ℝ) ∧ -∞
<ℝ -∞) | 
| 26 | 7 | nesymi 2413 | 
. . . . . . . 8
⊢  ¬
-∞ = +∞ | 
| 27 | 26 | intnan 930 | 
. . . . . . 7
⊢  ¬
(-∞ = -∞ ∧ -∞ = +∞) | 
| 28 | 25, 27 | pm3.2ni 814 | 
. . . . . 6
⊢  ¬
(((-∞ ∈ ℝ ∧ -∞ ∈ ℝ) ∧ -∞
<ℝ -∞) ∨ (-∞ = -∞ ∧ -∞ =
+∞)) | 
| 29 | 23 | intnanr 931 | 
. . . . . . 7
⊢  ¬
(-∞ ∈ ℝ ∧ -∞ = +∞) | 
| 30 | 23 | intnan 930 | 
. . . . . . 7
⊢  ¬
(-∞ = -∞ ∧ -∞ ∈ ℝ) | 
| 31 | 29, 30 | pm3.2ni 814 | 
. . . . . 6
⊢  ¬
((-∞ ∈ ℝ ∧ -∞ = +∞) ∨ (-∞ = -∞
∧ -∞ ∈ ℝ)) | 
| 32 | 28, 31 | pm3.2ni 814 | 
. . . . 5
⊢  ¬
((((-∞ ∈ ℝ ∧ -∞ ∈ ℝ) ∧ -∞
<ℝ -∞) ∨ (-∞ = -∞ ∧ -∞ =
+∞)) ∨ ((-∞ ∈ ℝ ∧ -∞ = +∞) ∨
(-∞ = -∞ ∧ -∞ ∈ ℝ))) | 
| 33 |   | mnfxr 8083 | 
. . . . . 6
⊢ -∞
∈ ℝ* | 
| 34 |   | ltxr 9850 | 
. . . . . 6
⊢
((-∞ ∈ ℝ* ∧ -∞ ∈
ℝ*) → (-∞ < -∞ ↔ ((((-∞ ∈
ℝ ∧ -∞ ∈ ℝ) ∧ -∞ <ℝ
-∞) ∨ (-∞ = -∞ ∧ -∞ = +∞)) ∨ ((-∞
∈ ℝ ∧ -∞ = +∞) ∨ (-∞ = -∞ ∧
-∞ ∈ ℝ))))) | 
| 35 | 33, 33, 34 | mp2an 426 | 
. . . . 5
⊢ (-∞
< -∞ ↔ ((((-∞ ∈ ℝ ∧ -∞ ∈ ℝ)
∧ -∞ <ℝ -∞) ∨ (-∞ = -∞ ∧
-∞ = +∞)) ∨ ((-∞ ∈ ℝ ∧ -∞ = +∞)
∨ (-∞ = -∞ ∧ -∞ ∈ ℝ)))) | 
| 36 | 32, 35 | mtbir 672 | 
. . . 4
⊢  ¬
-∞ < -∞ | 
| 37 |   | breq12 4038 | 
. . . . 5
⊢ ((𝐴 = -∞ ∧ 𝐴 = -∞) → (𝐴 < 𝐴 ↔ -∞ <
-∞)) | 
| 38 | 37 | anidms 397 | 
. . . 4
⊢ (𝐴 = -∞ → (𝐴 < 𝐴 ↔ -∞ <
-∞)) | 
| 39 | 36, 38 | mtbiri 676 | 
. . 3
⊢ (𝐴 = -∞ → ¬ 𝐴 < 𝐴) | 
| 40 | 2, 21, 39 | 3jaoi 1314 | 
. 2
⊢ ((𝐴 ∈ ℝ ∨ 𝐴 = +∞ ∨ 𝐴 = -∞) → ¬ 𝐴 < 𝐴) | 
| 41 | 1, 40 | sylbi 121 | 
1
⊢ (𝐴 ∈ ℝ*
→ ¬ 𝐴 < 𝐴) |