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Mirrors > Home > ILE Home > Th. List > xrex | GIF version |
Description: The set of extended reals exists. (Contributed by NM, 24-Dec-2006.) |
Ref | Expression |
---|---|
xrex | ⊢ ℝ* ∈ V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-xr 7828 | . 2 ⊢ ℝ* = (ℝ ∪ {+∞, -∞}) | |
2 | reex 7778 | . . 3 ⊢ ℝ ∈ V | |
3 | pnfxr 7842 | . . . 4 ⊢ +∞ ∈ ℝ* | |
4 | mnfxr 7846 | . . . 4 ⊢ -∞ ∈ ℝ* | |
5 | prexg 4141 | . . . 4 ⊢ ((+∞ ∈ ℝ* ∧ -∞ ∈ ℝ*) → {+∞, -∞} ∈ V) | |
6 | 3, 4, 5 | mp2an 423 | . . 3 ⊢ {+∞, -∞} ∈ V |
7 | 2, 6 | unex 4370 | . 2 ⊢ (ℝ ∪ {+∞, -∞}) ∈ V |
8 | 1, 7 | eqeltri 2213 | 1 ⊢ ℝ* ∈ V |
Colors of variables: wff set class |
Syntax hints: ∈ wcel 1481 Vcvv 2689 ∪ cun 3074 {cpr 3533 ℝcr 7643 +∞cpnf 7821 -∞cmnf 7822 ℝ*cxr 7823 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 699 ax-5 1424 ax-7 1425 ax-gen 1426 ax-ie1 1470 ax-ie2 1471 ax-8 1483 ax-10 1484 ax-11 1485 ax-i12 1486 ax-bndl 1487 ax-4 1488 ax-13 1492 ax-14 1493 ax-17 1507 ax-i9 1511 ax-ial 1515 ax-i5r 1516 ax-ext 2122 ax-sep 4054 ax-pow 4106 ax-pr 4139 ax-un 4363 ax-cnex 7735 ax-resscn 7736 |
This theorem depends on definitions: df-bi 116 df-tru 1335 df-nf 1438 df-sb 1737 df-clab 2127 df-cleq 2133 df-clel 2136 df-nfc 2271 df-rex 2423 df-v 2691 df-un 3080 df-in 3082 df-ss 3089 df-pw 3517 df-sn 3538 df-pr 3539 df-uni 3745 df-pnf 7826 df-mnf 7827 df-xr 7828 |
This theorem is referenced by: ixxval 9709 ixxf 9711 ixxex 9712 ispsmet 12531 isxmet 12553 xmetunirn 12566 blfvalps 12593 blex 12595 |
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