Proof of Theorem xmulgt0
| Step | Hyp | Ref
| Expression |
| 1 | | simpr 484 |
. . . . . 6
⊢ ((𝐴 ∈ ℝ*
∧ 0 < 𝐴) → 0
< 𝐴) |
| 2 | | simpr 484 |
. . . . . 6
⊢ ((𝐵 ∈ ℝ*
∧ 0 < 𝐵) → 0
< 𝐵) |
| 3 | 1, 2 | anim12i 613 |
. . . . 5
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → (0 < 𝐴 ∧ 0 < 𝐵)) |
| 4 | | mulgt0 11317 |
. . . . . . . 8
⊢ (((𝐴 ∈ ℝ ∧ 0 <
𝐴) ∧ (𝐵 ∈ ℝ ∧ 0 < 𝐵)) → 0 < (𝐴 · 𝐵)) |
| 5 | 4 | an4s 660 |
. . . . . . 7
⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) ∧ (0 <
𝐴 ∧ 0 < 𝐵)) → 0 < (𝐴 · 𝐵)) |
| 6 | 5 | ancoms 458 |
. . . . . 6
⊢ (((0 <
𝐴 ∧ 0 < 𝐵) ∧ (𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ)) → 0 < (𝐴 · 𝐵)) |
| 7 | | rexmul 13292 |
. . . . . . 7
⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 ·e 𝐵) = (𝐴 · 𝐵)) |
| 8 | 7 | adantl 481 |
. . . . . 6
⊢ (((0 <
𝐴 ∧ 0 < 𝐵) ∧ (𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ)) → (𝐴 ·e 𝐵) = (𝐴 · 𝐵)) |
| 9 | 6, 8 | breqtrrd 5152 |
. . . . 5
⊢ (((0 <
𝐴 ∧ 0 < 𝐵) ∧ (𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ)) → 0 < (𝐴 ·e 𝐵)) |
| 10 | 3, 9 | sylan 580 |
. . . 4
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ (𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ)) → 0 < (𝐴 ·e 𝐵)) |
| 11 | 10 | anassrs 467 |
. . 3
⊢
(((((𝐴 ∈
ℝ* ∧ 0 < 𝐴) ∧ (𝐵 ∈ ℝ* ∧ 0 <
𝐵)) ∧ 𝐴 ∈ ℝ) ∧ 𝐵 ∈ ℝ) → 0 < (𝐴 ·e 𝐵)) |
| 12 | | 0ltpnf 13143 |
. . . . 5
⊢ 0 <
+∞ |
| 13 | | oveq2 7418 |
. . . . . 6
⊢ (𝐵 = +∞ → (𝐴 ·e 𝐵) = (𝐴 ·e
+∞)) |
| 14 | | xmulpnf1 13295 |
. . . . . . 7
⊢ ((𝐴 ∈ ℝ*
∧ 0 < 𝐴) →
(𝐴 ·e
+∞) = +∞) |
| 15 | 14 | adantr 480 |
. . . . . 6
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → (𝐴 ·e +∞) =
+∞) |
| 16 | 13, 15 | sylan9eqr 2793 |
. . . . 5
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐵 = +∞) → (𝐴 ·e 𝐵) = +∞) |
| 17 | 12, 16 | breqtrrid 5162 |
. . . 4
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐵 = +∞) → 0 < (𝐴 ·e 𝐵)) |
| 18 | 17 | adantlr 715 |
. . 3
⊢
(((((𝐴 ∈
ℝ* ∧ 0 < 𝐴) ∧ (𝐵 ∈ ℝ* ∧ 0 <
𝐵)) ∧ 𝐴 ∈ ℝ) ∧ 𝐵 = +∞) → 0 < (𝐴 ·e 𝐵)) |
| 19 | | simplrr 777 |
. . . 4
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 ∈ ℝ) → 0 < 𝐵) |
| 20 | | xmulasslem2 13303 |
. . . 4
⊢ ((0 <
𝐵 ∧ 𝐵 = -∞) → 0 < (𝐴 ·e 𝐵)) |
| 21 | 19, 20 | sylan 580 |
. . 3
⊢
(((((𝐴 ∈
ℝ* ∧ 0 < 𝐴) ∧ (𝐵 ∈ ℝ* ∧ 0 <
𝐵)) ∧ 𝐴 ∈ ℝ) ∧ 𝐵 = -∞) → 0 < (𝐴 ·e 𝐵)) |
| 22 | | simprl 770 |
. . . . 5
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → 𝐵 ∈
ℝ*) |
| 23 | | elxr 13137 |
. . . . 5
⊢ (𝐵 ∈ ℝ*
↔ (𝐵 ∈ ℝ
∨ 𝐵 = +∞ ∨
𝐵 =
-∞)) |
| 24 | 22, 23 | sylib 218 |
. . . 4
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞ ∨ 𝐵 = -∞)) |
| 25 | 24 | adantr 480 |
. . 3
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 ∈ ℝ) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞ ∨ 𝐵 = -∞)) |
| 26 | 11, 18, 21, 25 | mpjao3dan 1434 |
. 2
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 ∈ ℝ) → 0 < (𝐴 ·e 𝐵)) |
| 27 | | oveq1 7417 |
. . . 4
⊢ (𝐴 = +∞ → (𝐴 ·e 𝐵) = (+∞
·e 𝐵)) |
| 28 | | xmulpnf2 13296 |
. . . . 5
⊢ ((𝐵 ∈ ℝ*
∧ 0 < 𝐵) →
(+∞ ·e 𝐵) = +∞) |
| 29 | 28 | adantl 481 |
. . . 4
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → (+∞ ·e
𝐵) =
+∞) |
| 30 | 27, 29 | sylan9eqr 2793 |
. . 3
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 = +∞) → (𝐴 ·e 𝐵) = +∞) |
| 31 | 12, 30 | breqtrrid 5162 |
. 2
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 = +∞) → 0 < (𝐴 ·e 𝐵)) |
| 32 | | xmulasslem2 13303 |
. . 3
⊢ ((0 <
𝐴 ∧ 𝐴 = -∞) → 0 < (𝐴 ·e 𝐵)) |
| 33 | 32 | ad4ant24 754 |
. 2
⊢ ((((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) ∧ 𝐴 = -∞) → 0 < (𝐴 ·e 𝐵)) |
| 34 | | simpll 766 |
. . 3
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → 𝐴 ∈
ℝ*) |
| 35 | | elxr 13137 |
. . 3
⊢ (𝐴 ∈ ℝ*
↔ (𝐴 ∈ ℝ
∨ 𝐴 = +∞ ∨
𝐴 =
-∞)) |
| 36 | 34, 35 | sylib 218 |
. 2
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → (𝐴 ∈ ℝ ∨ 𝐴 = +∞ ∨ 𝐴 = -∞)) |
| 37 | 26, 31, 33, 36 | mpjao3dan 1434 |
1
⊢ (((𝐴 ∈ ℝ*
∧ 0 < 𝐴) ∧
(𝐵 ∈
ℝ* ∧ 0 < 𝐵)) → 0 < (𝐴 ·e 𝐵)) |