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Mirrors > Home > ILE Home > Th. List > df-xr | Unicode version |
Description: Define the set of extended reals that includes plus and minus infinity. Definition 12-3.1 of [Gleason] p. 173. (Contributed by NM, 13-Oct-2005.) |
Ref | Expression |
---|---|
df-xr |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cxr 7799 | . 2 | |
2 | cr 7619 | . . 3 | |
3 | cpnf 7797 | . . . 4 | |
4 | cmnf 7798 | . . . 4 | |
5 | 3, 4 | cpr 3528 | . . 3 |
6 | 2, 5 | cun 3069 | . 2 |
7 | 1, 6 | wceq 1331 | 1 |
Colors of variables: wff set class |
This definition is referenced by: ressxr 7809 pnfxr 7818 mnfxr 7822 ltrelxr 7825 elxr 9563 xrex 9639 |
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