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Definition df-xr 9653
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 9648 . 2
2 cr 9512 . . 3
3 cpnf 9646 . . . 4
4 cmnf 9647 . . . 4
53, 4cpr 4031 . . 3
62, 5cun 3473 . 2
71, 6wceq 1395 1
Colors of variables: wff setvar class
This definition is referenced by:  ressxr  9658  ltrelxr  9669  ssxr  9675  xrex  11246  pnfxr  11350  mnfxr  11352  elxr  11354
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