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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 7961 | . . . 4 ⊢ +∞ ∉ ℝ | |
2 | 1 | neli 2437 | . . 3 ⊢ ¬ +∞ ∈ ℝ |
3 | eleq1 2233 | . . 3 ⊢ (𝐴 = +∞ → (𝐴 ∈ ℝ ↔ +∞ ∈ ℝ)) | |
4 | 2, 3 | mtbiri 670 | . 2 ⊢ (𝐴 = +∞ → ¬ 𝐴 ∈ ℝ) |
5 | 4 | necon2ai 2394 | 1 ⊢ (𝐴 ∈ ℝ → 𝐴 ≠ +∞) |
Colors of variables: wff set class |
Syntax hints: → wi 4 = wceq 1348 ∈ wcel 2141 ≠ wne 2340 ℝcr 7773 +∞cpnf 7951 |
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 609 ax-in2 610 ax-io 704 ax-5 1440 ax-7 1441 ax-gen 1442 ax-ie1 1486 ax-ie2 1487 ax-8 1497 ax-10 1498 ax-11 1499 ax-i12 1500 ax-bndl 1502 ax-4 1503 ax-17 1519 ax-i9 1523 ax-ial 1527 ax-i5r 1528 ax-13 2143 ax-14 2144 ax-ext 2152 ax-sep 4107 ax-un 4418 ax-cnex 7865 ax-resscn 7866 |
This theorem depends on definitions: df-bi 116 df-tru 1351 df-fal 1354 df-nf 1454 df-sb 1756 df-clab 2157 df-cleq 2163 df-clel 2166 df-nfc 2301 df-ne 2341 df-nel 2436 df-rex 2454 df-rab 2457 df-v 2732 df-in 3127 df-ss 3134 df-pw 3568 df-uni 3797 df-pnf 7956 |
This theorem is referenced by: renepnfd 7970 renfdisj 7979 ltxrlt 7985 xrnepnf 9735 xrlttri3 9754 nltpnft 9771 xrrebnd 9776 rexneg 9787 xrpnfdc 9799 rexadd 9809 xaddnepnf 9815 xaddcom 9818 xaddid1 9819 xnn0xadd0 9824 xnegdi 9825 xpncan 9828 xleadd1a 9830 xltadd1 9833 xsubge0 9838 xposdif 9839 xleaddadd 9844 xrmaxrecl 11218 |
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