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Mirrors > Home > ILE Home > Th. List > renepnf | GIF version |
Description: No (finite) real equals plus infinity. (Contributed by NM, 14-Oct-2005.) (Proof shortened by Andrew Salmon, 19-Nov-2011.) |
Ref | Expression |
---|---|
renepnf | ⊢ (𝐴 ∈ ℝ → 𝐴 ≠ +∞) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pnfnre 7814 | . . . 4 ⊢ +∞ ∉ ℝ | |
2 | 1 | neli 2405 | . . 3 ⊢ ¬ +∞ ∈ ℝ |
3 | eleq1 2202 | . . 3 ⊢ (𝐴 = +∞ → (𝐴 ∈ ℝ ↔ +∞ ∈ ℝ)) | |
4 | 2, 3 | mtbiri 664 | . 2 ⊢ (𝐴 = +∞ → ¬ 𝐴 ∈ ℝ) |
5 | 4 | necon2ai 2362 | 1 ⊢ (𝐴 ∈ ℝ → 𝐴 ≠ +∞) |
Colors of variables: wff set class |
Syntax hints: → wi 4 = wceq 1331 ∈ wcel 1480 ≠ wne 2308 ℝcr 7626 +∞cpnf 7804 |
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-in1 603 ax-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-13 1491 ax-14 1492 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 ax-sep 4046 ax-un 4355 ax-cnex 7718 ax-resscn 7719 |
This theorem depends on definitions: df-bi 116 df-tru 1334 df-fal 1337 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ne 2309 df-nel 2404 df-rex 2422 df-rab 2425 df-v 2688 df-in 3077 df-ss 3084 df-pw 3512 df-uni 3737 df-pnf 7809 |
This theorem is referenced by: renepnfd 7823 renfdisj 7831 ltxrlt 7837 xrnepnf 9572 xrlttri3 9590 nltpnft 9604 xrrebnd 9609 rexneg 9620 xrpnfdc 9632 rexadd 9642 xaddnepnf 9648 xaddcom 9651 xaddid1 9652 xnn0xadd0 9657 xnegdi 9658 xpncan 9661 xleadd1a 9663 xltadd1 9666 xsubge0 9671 xposdif 9672 xleaddadd 9677 xrmaxrecl 11031 |
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