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Mirrors > Home > ILE Home > Th. List > xaddmnf2 | GIF version |
Description: Addition of negative infinity on the left. (Contributed by Mario Carneiro, 20-Aug-2015.) |
Ref | Expression |
---|---|
xaddmnf2 | ⊢ ((𝐴 ∈ ℝ* ∧ 𝐴 ≠ +∞) → (-∞ +𝑒 𝐴) = -∞) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mnfxr 7829 | . . 3 ⊢ -∞ ∈ ℝ* | |
2 | xaddval 9635 | . . 3 ⊢ ((-∞ ∈ ℝ* ∧ 𝐴 ∈ ℝ*) → (-∞ +𝑒 𝐴) = if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴)))))) | |
3 | 1, 2 | mpan 420 | . 2 ⊢ (𝐴 ∈ ℝ* → (-∞ +𝑒 𝐴) = if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴)))))) |
4 | mnfnepnf 7828 | . . . . 5 ⊢ -∞ ≠ +∞ | |
5 | ifnefalse 3485 | . . . . 5 ⊢ (-∞ ≠ +∞ → if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴))))) = if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴))))) | |
6 | 4, 5 | ax-mp 5 | . . . 4 ⊢ if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴))))) = if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴)))) |
7 | eqid 2139 | . . . . 5 ⊢ -∞ = -∞ | |
8 | 7 | iftruei 3480 | . . . 4 ⊢ if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴)))) = if(𝐴 = +∞, 0, -∞) |
9 | 6, 8 | eqtri 2160 | . . 3 ⊢ if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴))))) = if(𝐴 = +∞, 0, -∞) |
10 | ifnefalse 3485 | . . 3 ⊢ (𝐴 ≠ +∞ → if(𝐴 = +∞, 0, -∞) = -∞) | |
11 | 9, 10 | syl5eq 2184 | . 2 ⊢ (𝐴 ≠ +∞ → if(-∞ = +∞, if(𝐴 = -∞, 0, +∞), if(-∞ = -∞, if(𝐴 = +∞, 0, -∞), if(𝐴 = +∞, +∞, if(𝐴 = -∞, -∞, (-∞ + 𝐴))))) = -∞) |
12 | 3, 11 | sylan9eq 2192 | 1 ⊢ ((𝐴 ∈ ℝ* ∧ 𝐴 ≠ +∞) → (-∞ +𝑒 𝐴) = -∞) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 = wceq 1331 ∈ wcel 1480 ≠ wne 2308 ifcif 3474 (class class class)co 5774 0cc0 7627 + caddc 7630 +∞cpnf 7804 -∞cmnf 7805 ℝ*cxr 7806 +𝑒 cxad 9564 |
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-pow 4098 ax-pr 4131 ax-un 4355 ax-setind 4452 ax-cnex 7718 ax-resscn 7719 ax-1re 7721 ax-addrcl 7724 ax-rnegex 7736 |
This theorem depends on definitions: df-bi 116 df-dc 820 df-3or 963 df-3an 964 df-tru 1334 df-fal 1337 df-nf 1437 df-sb 1736 df-eu 2002 df-mo 2003 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ne 2309 df-nel 2404 df-ral 2421 df-rex 2422 df-rab 2425 df-v 2688 df-sbc 2910 df-dif 3073 df-un 3075 df-in 3077 df-ss 3084 df-if 3475 df-pw 3512 df-sn 3533 df-pr 3534 df-op 3536 df-uni 3737 df-br 3930 df-opab 3990 df-id 4215 df-xp 4545 df-rel 4546 df-cnv 4547 df-co 4548 df-dm 4549 df-iota 5088 df-fun 5125 df-fv 5131 df-ov 5777 df-oprab 5778 df-mpo 5779 df-pnf 7809 df-mnf 7810 df-xr 7811 df-xadd 9567 |
This theorem is referenced by: xaddnepnf 9648 xaddcom 9651 xaddid1 9652 xnegdi 9658 xpncan 9661 xleadd1a 9663 xltadd1 9666 xlt2add 9670 xposdif 9672 xleaddadd 9677 xrmaxadd 11037 |
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