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Definition df-xr 9175
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 9170 . 2
2 cr 9040 . . 3
3 cpnf 9168 . . . 4
4 cmnf 9169 . . . 4
53, 4cpr 3842 . . 3
62, 5cun 3307 . 2
71, 6wceq 1654 1
Colors of variables: wff set class
This definition is referenced by:  ressxr  9180  ltrelxr  9190  ssxr  9196  xrex  10660  pnfxr  10764  mnfxr  10765  elxr  10767
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