ltpnf - Intuitionistic Logic Explorer

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Theorem ltpnf 10015

Description: Any (finite) real is less than plus infinity. (Contributed by NM, 14-Oct-2005.)

**Assertion**
Ref	Expression
ltpnf	⊢ (𝐴 ∈ ℝ → 𝐴 < +∞)

**Proof of Theorem ltpnf**
Step	Hyp	Ref	Expression
1		eqid 2231	. . . 4 ⊢ +∞ = +∞
2		orc 719	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ +∞ = +∞) → ((𝐴 ∈ ℝ ∧ +∞ = +∞) ∨ (𝐴 = -∞ ∧ +∞ ∈ ℝ)))
3	1, 2	mpan2 425	. . 3 ⊢ (𝐴 ∈ ℝ → ((𝐴 ∈ ℝ ∧ +∞ = +∞) ∨ (𝐴 = -∞ ∧ +∞ ∈ ℝ)))
4	3	olcd 741	. 2 ⊢ (𝐴 ∈ ℝ → ((((𝐴 ∈ ℝ ∧ +∞ ∈ ℝ) ∧ 𝐴 <_ℝ +∞) ∨ (𝐴 = -∞ ∧ +∞ = +∞)) ∨ ((𝐴 ∈ ℝ ∧ +∞ = +∞) ∨ (𝐴 = -∞ ∧ +∞ ∈ ℝ))))
5		rexr 8225	. . 3 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℝ^*)
6		pnfxr 8232	. . 3 ⊢ +∞ ∈ ℝ^*
7		ltxr 10010	. . 3 ⊢ ((𝐴 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) → (𝐴 < +∞ ↔ ((((𝐴 ∈ ℝ ∧ +∞ ∈ ℝ) ∧ 𝐴 <_ℝ +∞) ∨ (𝐴 = -∞ ∧ +∞ = +∞)) ∨ ((𝐴 ∈ ℝ ∧ +∞ = +∞) ∨ (𝐴 = -∞ ∧ +∞ ∈ ℝ)))))
8	5, 6, 7	sylancl 413	. 2 ⊢ (𝐴 ∈ ℝ → (𝐴 < +∞ ↔ ((((𝐴 ∈ ℝ ∧ +∞ ∈ ℝ) ∧ 𝐴 <_ℝ +∞) ∨ (𝐴 = -∞ ∧ +∞ = +∞)) ∨ ((𝐴 ∈ ℝ ∧ +∞ = +∞) ∨ (𝐴 = -∞ ∧ +∞ ∈ ℝ)))))
9	4, 8	mpbird 167	1 ⊢ (𝐴 ∈ ℝ → 𝐴 < +∞)

Colors of variables: wff set class

Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 ∨ wo 715 = wceq 1397 ∈ wcel 2202 class class class wbr 4088 ℝcr 8031 <_ℝ cltrr 8036 +∞cpnf 8211 -∞cmnf 8212 ℝ^*cxr 8213 < clt 8214

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 716 ax-5 1495 ax-7 1496 ax-gen 1497 ax-ie1 1541 ax-ie2 1542 ax-8 1552 ax-10 1553 ax-11 1554 ax-i12 1555 ax-bndl 1557 ax-4 1558 ax-17 1574 ax-i9 1578 ax-ial 1582 ax-i5r 1583 ax-13 2204 ax-14 2205 ax-ext 2213 ax-sep 4207 ax-pow 4264 ax-pr 4299 ax-un 4530 ax-cnex 8123

This theorem depends on definitions: df-bi 117 df-3an 1006 df-tru 1400 df-nf 1509 df-sb 1811 df-eu 2082 df-mo 2083 df-clab 2218 df-cleq 2224 df-clel 2227 df-nfc 2363 df-ral 2515 df-rex 2516 df-v 2804 df-un 3204 df-in 3206 df-ss 3213 df-pw 3654 df-sn 3675 df-pr 3676 df-op 3678 df-uni 3894 df-br 4089 df-opab 4151 df-xp 4731 df-pnf 8216 df-xr 8218 df-ltxr 8219

This theorem is referenced by: ltpnfd 10016 0ltpnf 10017 xrlttr 10030 xrltso 10031 xrlttri3 10032 nltpnft 10049 npnflt 10050 xrrebnd 10054 xrre 10055 xltnegi 10070 xltadd1 10111 xposdif 10117 elioc2 10171 elicc2 10173 ioomax 10183 ioopos 10185 elioopnf 10202 elicopnf 10204 qbtwnxr 10518 dfrp2 10524 filtinf 11054 xrmaxltsup 11836 fprodge0 12216 fprodge1 12218 xblss2ps 15147

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