xrred - Mathbox for Glauco Siliprandi

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Theorem xrred 46469

Description: An extended real that is neither minus infinity, nor plus infinity, is real. (Contributed by Glauco Siliprandi, 3-Mar-2021.)

**Hypotheses**
Ref	Expression
xrred.1	⊢ (𝜑 → 𝐴 ∈ ℝ^*)
xrred.2	⊢ (𝜑 → 𝐴 ≠ -∞)
xrred.3	⊢ (𝜑 → 𝐴 ≠ +∞)

**Assertion**
Ref	Expression
xrred	⊢ (𝜑 → 𝐴 ∈ ℝ)

**Proof of Theorem xrred**
Step	Hyp	Ref	Expression
1		xrred.1	. . . 4 ⊢ (𝜑 → 𝐴 ∈ ℝ^*)
2		xrred.2	. . . 4 ⊢ (𝜑 → 𝐴 ≠ -∞)
3	1, 2	jca 521	. . 3 ⊢ (𝜑 → (𝐴 ∈ ℝ^* ∧ 𝐴 ≠ -∞))
4		xrnemnf 13249	. . 3 ⊢ ((𝐴 ∈ ℝ^* ∧ 𝐴 ≠ -∞) ↔ (𝐴 ∈ ℝ ∨ 𝐴 = +∞))
5	3, 4	sylib 221	. 2 ⊢ (𝜑 → (𝐴 ∈ ℝ ∨ 𝐴 = +∞))
6		xrred.3	. . 3 ⊢ (𝜑 → 𝐴 ≠ +∞)
7	6	neneqd 2960	. 2 ⊢ (𝜑 → ¬ 𝐴 = +∞)
8		pm2.53 865	. . 3 ⊢ ((𝐴 ∈ ℝ ∨ 𝐴 = +∞) → (¬ 𝐴 ∈ ℝ → 𝐴 = +∞))
9	8	con1d 146	. 2 ⊢ ((𝐴 ∈ ℝ ∨ 𝐴 = +∞) → (¬ 𝐴 = +∞ → 𝐴 ∈ ℝ))
10	5, 7, 9	sylc 66	1 ⊢ (𝜑 → 𝐴 ∈ ℝ)

Colors of variables: wff setvar class

This proof depends on syntax axioms: ¬ wn 3 → wi 4 ∧ wa 401 ∨ wo 861 = wceq 1569 ∈ wcel 2144 ≠ wne 2955 ℝcr 11202 +∞cpnf 11343 -∞cmnf 11344 ℝ^*cxr 11345

This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1827 ax-4 1841 ax-5 1942 ax-6 1999 ax-7 2040 ax-8 2146 ax-9 2154 ax-10 2177 ax-11 2193 ax-12 2212 ax-ext 2732 ax-sep 5248 ax-nul 5259 ax-pow 5326 ax-pr 5390 ax-un 7751 ax-cnex 11259 ax-resscn 11260

This proof depends on definitions: df-bi 210 df-an 402 df-or 862 df-3or 1104 df-3an 1105 df-tru 1572 df-fal 1582 df-ex 1812 df-nf 1816 df-sb 2099 df-mo 2564 df-eu 2594 df-clab 2739 df-cleq 2752 df-clel 2835 df-nfc 2909 df-ne 2956 df-nel 3062 df-ral 3077 df-rex 3087 df-rab 3413 df-v 3452 df-sbc 3739 df-csb 3847 df-ss 3896 df-dif 4047 df-in 4091 df-un 4151 df-nul 4279 df-if 4482 df-pw 4558 df-sn 4585 df-pr 4587 df-op 4835 df-uni 4867 df-br 5103 df-opab 5167 df-mpt 5186 df-id 5545 df-xp 5656 df-rel 5657 df-cnv 5658 df-co 5659 df-dm 5660 df-rn 5661 df-res 5662 df-ima 5663 df-iota 6494 df-fun 6540 df-fn 6541 df-f 6542 df-f1 6543 df-fo 6544 df-f1o 6545 df-fv 6546 df-er 8720 df-en 8977 df-dom 8978 df-sdom 8979 df-pnf 11348 df-mnf 11349 df-xr 11350

This theorem is used by: infxr 46471 infleinflem2 46475 xrralrecnnge 46494 xrre4 46514 supminfxr2 46572 xrpnf 46588 climxrrelem 46852 climxrre 46853 liminflimsupxrre 46920 ioorrnopnxrlem 47409 pimiooltgt 47813 smfpimltxr 47850 smfpimgtxr 47883

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