nepnfltpnf - Mathbox for Glauco Siliprandi

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Theorem nepnfltpnf 44859

Description: An extended real that is not +∞ is less than +∞. (Contributed by Glauco Siliprandi, 11-Oct-2020.)

**Hypotheses**
Ref	Expression
nepnfltpnf.1	⊢ (𝜑 → 𝐴 ≠ +∞)
nepnfltpnf.2	⊢ (𝜑 → 𝐴 ∈ ℝ^*)

**Assertion**
Ref	Expression
nepnfltpnf	⊢ (𝜑 → 𝐴 < +∞)

**Proof of Theorem nepnfltpnf**
Step	Hyp	Ref	Expression
1		nepnfltpnf.1	. . . 4 ⊢ (𝜑 → 𝐴 ≠ +∞)
2	1	neneqd 2934	. . 3 ⊢ (𝜑 → ¬ 𝐴 = +∞)
3		nepnfltpnf.2	. . . 4 ⊢ (𝜑 → 𝐴 ∈ ℝ^*)
4		nltpnft 13178	. . . 4 ⊢ (𝐴 ∈ ℝ^* → (𝐴 = +∞ ↔ ¬ 𝐴 < +∞))
5	3, 4	syl 17	. . 3 ⊢ (𝜑 → (𝐴 = +∞ ↔ ¬ 𝐴 < +∞))
6	2, 5	mtbid 323	. 2 ⊢ (𝜑 → ¬ ¬ 𝐴 < +∞)
7		notnotb 314	. 2 ⊢ (𝐴 < +∞ ↔ ¬ ¬ 𝐴 < +∞)
8	6, 7	sylibr 233	1 ⊢ (𝜑 → 𝐴 < +∞)

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 = wceq 1533 ∈ wcel 2098 ≠ wne 2929 class class class wbr 5149 +∞cpnf 11277 ℝ^*cxr 11279 < clt 11280

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2166 ax-ext 2696 ax-sep 5300 ax-nul 5307 ax-pow 5365 ax-pr 5429 ax-un 7741 ax-cnex 11196 ax-resscn 11197 ax-pre-lttri 11214 ax-pre-lttrn 11215

This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2703 df-cleq 2717 df-clel 2802 df-nfc 2877 df-ne 2930 df-nel 3036 df-ral 3051 df-rex 3060 df-rab 3419 df-v 3463 df-sbc 3774 df-csb 3890 df-dif 3947 df-un 3949 df-in 3951 df-ss 3961 df-nul 4323 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4910 df-br 5150 df-opab 5212 df-mpt 5233 df-id 5576 df-po 5590 df-so 5591 df-xp 5684 df-rel 5685 df-cnv 5686 df-co 5687 df-dm 5688 df-rn 5689 df-res 5690 df-ima 5691 df-iota 6501 df-fun 6551 df-fn 6552 df-f 6553 df-f1 6554 df-fo 6555 df-f1o 6556 df-fv 6557 df-er 8725 df-en 8965 df-dom 8966 df-sdom 8967 df-pnf 11282 df-mnf 11283 df-xr 11284 df-ltxr 11285 df-le 11286

This theorem is referenced by: infrpge 44868