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Mirrors > Home > ILE Home > Th. List > xrrebnd | GIF version |
Description: An extended real is real iff it is strictly bounded by infinities. (Contributed by NM, 2-Feb-2006.) |
Ref | Expression |
---|---|
xrrebnd | ⊢ (𝐴 ∈ ℝ* → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elxr 8696 | . 2 ⊢ (𝐴 ∈ ℝ* ↔ (𝐴 ∈ ℝ ∨ 𝐴 = +∞ ∨ 𝐴 = -∞)) | |
2 | id 19 | . . . 4 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℝ) | |
3 | mnflt 8704 | . . . . 5 ⊢ (𝐴 ∈ ℝ → -∞ < 𝐴) | |
4 | ltpnf 8702 | . . . . 5 ⊢ (𝐴 ∈ ℝ → 𝐴 < +∞) | |
5 | 3, 4 | jca 290 | . . . 4 ⊢ (𝐴 ∈ ℝ → (-∞ < 𝐴 ∧ 𝐴 < +∞)) |
6 | 2, 5 | 2thd 164 | . . 3 ⊢ (𝐴 ∈ ℝ → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
7 | renepnf 7073 | . . . . 5 ⊢ (𝐴 ∈ ℝ → 𝐴 ≠ +∞) | |
8 | 7 | necon2bi 2260 | . . . 4 ⊢ (𝐴 = +∞ → ¬ 𝐴 ∈ ℝ) |
9 | pnfxr 8692 | . . . . . . 7 ⊢ +∞ ∈ ℝ* | |
10 | xrltnr 8701 | . . . . . . 7 ⊢ (+∞ ∈ ℝ* → ¬ +∞ < +∞) | |
11 | 9, 10 | ax-mp 7 | . . . . . 6 ⊢ ¬ +∞ < +∞ |
12 | breq1 3767 | . . . . . 6 ⊢ (𝐴 = +∞ → (𝐴 < +∞ ↔ +∞ < +∞)) | |
13 | 11, 12 | mtbiri 600 | . . . . 5 ⊢ (𝐴 = +∞ → ¬ 𝐴 < +∞) |
14 | 13 | intnand 840 | . . . 4 ⊢ (𝐴 = +∞ → ¬ (-∞ < 𝐴 ∧ 𝐴 < +∞)) |
15 | 8, 14 | 2falsed 618 | . . 3 ⊢ (𝐴 = +∞ → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
16 | renemnf 7074 | . . . . 5 ⊢ (𝐴 ∈ ℝ → 𝐴 ≠ -∞) | |
17 | 16 | necon2bi 2260 | . . . 4 ⊢ (𝐴 = -∞ → ¬ 𝐴 ∈ ℝ) |
18 | mnfxr 8694 | . . . . . . 7 ⊢ -∞ ∈ ℝ* | |
19 | xrltnr 8701 | . . . . . . 7 ⊢ (-∞ ∈ ℝ* → ¬ -∞ < -∞) | |
20 | 18, 19 | ax-mp 7 | . . . . . 6 ⊢ ¬ -∞ < -∞ |
21 | breq2 3768 | . . . . . 6 ⊢ (𝐴 = -∞ → (-∞ < 𝐴 ↔ -∞ < -∞)) | |
22 | 20, 21 | mtbiri 600 | . . . . 5 ⊢ (𝐴 = -∞ → ¬ -∞ < 𝐴) |
23 | 22 | intnanrd 841 | . . . 4 ⊢ (𝐴 = -∞ → ¬ (-∞ < 𝐴 ∧ 𝐴 < +∞)) |
24 | 17, 23 | 2falsed 618 | . . 3 ⊢ (𝐴 = -∞ → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
25 | 6, 15, 24 | 3jaoi 1198 | . 2 ⊢ ((𝐴 ∈ ℝ ∨ 𝐴 = +∞ ∨ 𝐴 = -∞) → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
26 | 1, 25 | sylbi 114 | 1 ⊢ (𝐴 ∈ ℝ* → (𝐴 ∈ ℝ ↔ (-∞ < 𝐴 ∧ 𝐴 < +∞))) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 97 ↔ wb 98 ∨ w3o 884 = wceq 1243 ∈ wcel 1393 class class class wbr 3764 ℝcr 6888 +∞cpnf 7057 -∞cmnf 7058 ℝ*cxr 7059 < clt 7060 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 ax-io 630 ax-5 1336 ax-7 1337 ax-gen 1338 ax-ie1 1382 ax-ie2 1383 ax-8 1395 ax-10 1396 ax-11 1397 ax-i12 1398 ax-bndl 1399 ax-4 1400 ax-13 1404 ax-14 1405 ax-17 1419 ax-i9 1423 ax-ial 1427 ax-i5r 1428 ax-ext 2022 ax-sep 3875 ax-pow 3927 ax-pr 3944 ax-un 4170 ax-setind 4262 ax-cnex 6975 ax-resscn 6976 ax-pre-ltirr 6996 |
This theorem depends on definitions: df-bi 110 df-3or 886 df-3an 887 df-tru 1246 df-fal 1249 df-nf 1350 df-sb 1646 df-eu 1903 df-mo 1904 df-clab 2027 df-cleq 2033 df-clel 2036 df-nfc 2167 df-ne 2206 df-nel 2207 df-ral 2311 df-rex 2312 df-rab 2315 df-v 2559 df-dif 2920 df-un 2922 df-in 2924 df-ss 2931 df-pw 3361 df-sn 3381 df-pr 3382 df-op 3384 df-uni 3581 df-br 3765 df-opab 3819 df-xp 4351 df-pnf 7062 df-mnf 7063 df-xr 7064 df-ltxr 7065 |
This theorem is referenced by: xrre 8733 xrre2 8734 xrre3 8735 elioc2 8805 elico2 8806 elicc2 8807 |
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