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Theorem nltpnft 12898

Description: An extended real is not less than plus infinity iff they are equal. (Contributed by NM, 30-Jan-2006.)

**Assertion**
Ref	Expression
nltpnft	⊢ (𝐴 ∈ ℝ^* → (𝐴 = +∞ ↔ ¬ 𝐴 < +∞))

**Proof of Theorem nltpnft**
Step	Hyp	Ref	Expression
1		pnfxr 11029	. . . 4 ⊢ +∞ ∈ ℝ^*
2		xrltnr 12855	. . . 4 ⊢ (+∞ ∈ ℝ^* → ¬ +∞ < +∞)
3	1, 2	ax-mp 5	. . 3 ⊢ ¬ +∞ < +∞
4		breq1 5077	. . 3 ⊢ (𝐴 = +∞ → (𝐴 < +∞ ↔ +∞ < +∞))
5	3, 4	mtbiri 327	. 2 ⊢ (𝐴 = +∞ → ¬ 𝐴 < +∞)
6		pnfge 12866	. . . 4 ⊢ (𝐴 ∈ ℝ^* → 𝐴 ≤ +∞)
7		xrleloe 12878	. . . . 5 ⊢ ((𝐴 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) → (𝐴 ≤ +∞ ↔ (𝐴 < +∞ ∨ 𝐴 = +∞)))
8	1, 7	mpan2 688	. . . 4 ⊢ (𝐴 ∈ ℝ^* → (𝐴 ≤ +∞ ↔ (𝐴 < +∞ ∨ 𝐴 = +∞)))
9	6, 8	mpbid 231	. . 3 ⊢ (𝐴 ∈ ℝ^* → (𝐴 < +∞ ∨ 𝐴 = +∞))
10	9	ord 861	. 2 ⊢ (𝐴 ∈ ℝ^* → (¬ 𝐴 < +∞ → 𝐴 = +∞))
11	5, 10	impbid2 225	1 ⊢ (𝐴 ∈ ℝ^* → (𝐴 = +∞ ↔ ¬ 𝐴 < +∞))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∨ wo 844 = wceq 1539 ∈ wcel 2106 class class class wbr 5074 +∞cpnf 11006 ℝ^*cxr 11008 < clt 11009 ≤ cle 11010

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2709 ax-sep 5223 ax-nul 5230 ax-pow 5288 ax-pr 5352 ax-un 7588 ax-cnex 10927 ax-resscn 10928 ax-pre-lttri 10945 ax-pre-lttrn 10946

This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1542 df-fal 1552 df-ex 1783 df-nf 1787 df-sb 2068 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2816 df-nfc 2889 df-ne 2944 df-nel 3050 df-ral 3069 df-rex 3070 df-rab 3073 df-v 3434 df-sbc 3717 df-csb 3833 df-dif 3890 df-un 3892 df-in 3894 df-ss 3904 df-nul 4257 df-if 4460 df-pw 4535 df-sn 4562 df-pr 4564 df-op 4568 df-uni 4840 df-br 5075 df-opab 5137 df-mpt 5158 df-id 5489 df-po 5503 df-so 5504 df-xp 5595 df-rel 5596 df-cnv 5597 df-co 5598 df-dm 5599 df-rn 5600 df-res 5601 df-ima 5602 df-iota 6391 df-fun 6435 df-fn 6436 df-f 6437 df-f1 6438 df-fo 6439 df-f1o 6440 df-fv 6441 df-er 8498 df-en 8734 df-dom 8735 df-sdom 8736 df-pnf 11011 df-mnf 11012 df-xr 11013 df-ltxr 11014 df-le 11015

This theorem is referenced by: xgepnf 12899 xrrebnd 12902 xlt2add 12994 supxrbnd1 13055 supxrbnd2 13056 supxrgtmnf 13063 supxrre2 13065 ioopnfsup 13584 icopnfsup 13585 xrsdsreclblem 20644 ovoliun 24669 ovolicopnf 24688 voliunlem3 24716 volsup 24720 itg2seq 24907 nmoreltpnf 29131 nmopreltpnf 30231 ismblfin 35818 supxrgere 42872 supxrgelem 42876 supxrge 42877 suplesup 42878 nepnfltpnf 42881 xrpnf 43026 sge0repnf 43924 sge0rpcpnf 43959 sge0rernmpt 43960

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