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Theorem pnf0xnn0 9143
 Description: Positive infinity is an extended nonnegative integer. (Contributed by AV, 10-Dec-2020.)
Assertion
Ref Expression
pnf0xnn0 +∞ ∈ ℕ0*

Proof of Theorem pnf0xnn0
StepHypRef Expression
1 eqid 2157 . . 3 +∞ = +∞
21olci 722 . 2 (+∞ ∈ ℕ0 ∨ +∞ = +∞)
3 elxnn0 9138 . 2 (+∞ ∈ ℕ0* ↔ (+∞ ∈ ℕ0 ∨ +∞ = +∞))
42, 3mpbir 145 1 +∞ ∈ ℕ0*
 Colors of variables: wff set class Syntax hints:   ∨ wo 698   = wceq 1335   ∈ wcel 2128  +∞cpnf 7892  ℕ0cn0 9073  ℕ0*cxnn0 9136 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1427  ax-7 1428  ax-gen 1429  ax-ie1 1473  ax-ie2 1474  ax-8 1484  ax-10 1485  ax-11 1486  ax-i12 1487  ax-bndl 1489  ax-4 1490  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-13 2130  ax-14 2131  ax-ext 2139  ax-sep 4082  ax-pow 4134  ax-un 4392  ax-cnex 7806 This theorem depends on definitions:  df-bi 116  df-tru 1338  df-nf 1441  df-sb 1743  df-clab 2144  df-cleq 2150  df-clel 2153  df-nfc 2288  df-rex 2441  df-v 2714  df-un 3106  df-in 3108  df-ss 3115  df-pw 3545  df-sn 3566  df-pr 3567  df-uni 3773  df-pnf 7897  df-xr 7899  df-xnn0 9137 This theorem is referenced by:  inftonninf  10322
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