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Definition df-xr 9301
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.)
Assertion
Ref Expression
df-xr

Detailed syntax breakdown of Definition df-xr
StepHypRef Expression
1 cxr 9296 . 2
2 cr 9160 . . 3
3 cpnf 9294 . . . 4
4 cmnf 9295 . . . 4
53, 4cpr 3910 . . 3
62, 5cun 3363 . 2
71, 6wceq 1670 1
Colors of variables: wff set class
This definition is referenced by:  ressxr  9306  ltrelxr  9317  ssxr  9323  xrex  10852  pnfxr  10956  mnfxr  10958  elxr  10960
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