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Mirrors > Home > MPE Home > Th. List > xnegex | Structured version Visualization version GIF version |
Description: A negative extended real exists as a set. (Contributed by Mario Carneiro, 20-Aug-2015.) |
Ref | Expression |
---|---|
xnegex | ⊢ -𝑒𝐴 ∈ V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-xneg 11822 | . 2 ⊢ -𝑒𝐴 = if(𝐴 = +∞, -∞, if(𝐴 = -∞, +∞, -𝐴)) | |
2 | mnfxr 9975 | . . . 4 ⊢ -∞ ∈ ℝ* | |
3 | 2 | elexi 3186 | . . 3 ⊢ -∞ ∈ V |
4 | pnfex 9972 | . . . 4 ⊢ +∞ ∈ V | |
5 | negex 10158 | . . . 4 ⊢ -𝐴 ∈ V | |
6 | 4, 5 | ifex 4106 | . . 3 ⊢ if(𝐴 = -∞, +∞, -𝐴) ∈ V |
7 | 3, 6 | ifex 4106 | . 2 ⊢ if(𝐴 = +∞, -∞, if(𝐴 = -∞, +∞, -𝐴)) ∈ V |
8 | 1, 7 | eqeltri 2684 | 1 ⊢ -𝑒𝐴 ∈ V |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1475 ∈ wcel 1977 Vcvv 3173 ifcif 4036 +∞cpnf 9950 -∞cmnf 9951 ℝ*cxr 9952 -cneg 10146 -𝑒cxne 11819 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-8 1979 ax-9 1986 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 ax-sep 4709 ax-nul 4717 ax-pow 4769 ax-un 6847 ax-cnex 9871 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-eu 2462 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ral 2901 df-rex 2902 df-v 3175 df-sbc 3403 df-dif 3543 df-un 3545 df-in 3547 df-ss 3554 df-nul 3875 df-if 4037 df-pw 4110 df-sn 4126 df-pr 4128 df-uni 4373 df-iota 5768 df-fv 5812 df-ov 6552 df-pnf 9955 df-mnf 9956 df-xr 9957 df-neg 10148 df-xneg 11822 |
This theorem is referenced by: xrhmeo 22553 |
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