supxrbnd1 - Metamath Proof Explorer

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Theorem supxrbnd1 12315

Description: The supremum of a bounded-above set of extended reals is less than infinity. (Contributed by NM, 30-Jan-2006.)

**Assertion**
Ref	Expression
supxrbnd1	⊢ (𝐴 ⊆ ℝ^* → (∃𝑥 ∈ ℝ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ sup(𝐴, ℝ^*, < ) < +∞))

Distinct variable group: 𝑥,𝑦,𝐴

**Proof of Theorem supxrbnd1**
Step	Hyp	Ref	Expression
1		ralnex 3118	. . . 4 ⊢ (∀𝑥 ∈ ℝ ¬ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ ¬ ∃𝑥 ∈ ℝ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥)
2		rexr 10248	. . . . . . . . 9 ⊢ (𝑥 ∈ ℝ → 𝑥 ∈ ℝ^*)
3		ssel2 3727	. . . . . . . . 9 ⊢ ((𝐴 ⊆ ℝ^* ∧ 𝑦 ∈ 𝐴) → 𝑦 ∈ ℝ^*)
4		xrlenlt 10266	. . . . . . . . 9 ⊢ ((𝑥 ∈ ℝ^* ∧ 𝑦 ∈ ℝ^*) → (𝑥 ≤ 𝑦 ↔ ¬ 𝑦 < 𝑥))
5	2, 3, 4	syl2anr 496	. . . . . . . 8 ⊢ (((𝐴 ⊆ ℝ^* ∧ 𝑦 ∈ 𝐴) ∧ 𝑥 ∈ ℝ) → (𝑥 ≤ 𝑦 ↔ ¬ 𝑦 < 𝑥))
6	5	an32s 881	. . . . . . 7 ⊢ (((𝐴 ⊆ ℝ^* ∧ 𝑥 ∈ ℝ) ∧ 𝑦 ∈ 𝐴) → (𝑥 ≤ 𝑦 ↔ ¬ 𝑦 < 𝑥))
7	6	rexbidva 3175	. . . . . 6 ⊢ ((𝐴 ⊆ ℝ^* ∧ 𝑥 ∈ ℝ) → (∃𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ ∃𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥))
8		rexnal 3121	. . . . . 6 ⊢ (∃𝑦 ∈ 𝐴 ¬ 𝑦 < 𝑥 ↔ ¬ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥)
9	7, 8	syl6rbb 277	. . . . 5 ⊢ ((𝐴 ⊆ ℝ^* ∧ 𝑥 ∈ ℝ) → (¬ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ ∃𝑦 ∈ 𝐴 𝑥 ≤ 𝑦))
10	9	ralbidva 3111	. . . 4 ⊢ (𝐴 ⊆ ℝ^* → (∀𝑥 ∈ ℝ ¬ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ ∀𝑥 ∈ ℝ ∃𝑦 ∈ 𝐴 𝑥 ≤ 𝑦))
11	1, 10	syl5bbr 274	. . 3 ⊢ (𝐴 ⊆ ℝ^* → (¬ ∃𝑥 ∈ ℝ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ ∀𝑥 ∈ ℝ ∃𝑦 ∈ 𝐴 𝑥 ≤ 𝑦))
12		supxrunb1 12313	. . 3 ⊢ (𝐴 ⊆ ℝ^* → (∀𝑥 ∈ ℝ ∃𝑦 ∈ 𝐴 𝑥 ≤ 𝑦 ↔ sup(𝐴, ℝ^*, < ) = +∞))
13		supxrcl 12309	. . . 4 ⊢ (𝐴 ⊆ ℝ^* → sup(𝐴, ℝ^, < ) ∈ ℝ^)
14		nltpnft 12159	. . . 4 ⊢ (sup(𝐴, ℝ^, < ) ∈ ℝ^ → (sup(𝐴, ℝ^, < ) = +∞ ↔ ¬ sup(𝐴, ℝ^, < ) < +∞))
15	13, 14	syl 17	. . 3 ⊢ (𝐴 ⊆ ℝ^* → (sup(𝐴, ℝ^, < ) = +∞ ↔ ¬ sup(𝐴, ℝ^, < ) < +∞))
16	11, 12, 15	3bitrd 294	. 2 ⊢ (𝐴 ⊆ ℝ^* → (¬ ∃𝑥 ∈ ℝ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ ¬ sup(𝐴, ℝ^*, < ) < +∞))
17	16	con4bid 306	1 ⊢ (𝐴 ⊆ ℝ^* → (∃𝑥 ∈ ℝ ∀𝑦 ∈ 𝐴 𝑦 < 𝑥 ↔ sup(𝐴, ℝ^*, < ) < +∞))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 196 ∧ wa 383 = wceq 1620 ∈ wcel 2127 ∀wral 3038 ∃wrex 3039 ⊆ wss 3703 class class class wbr 4792 supcsup 8499 ℝcr 10098 +∞cpnf 10234 ℝ^*cxr 10236 < clt 10237 ≤ cle 10238

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1859 ax-4 1874 ax-5 1976 ax-6 2042 ax-7 2078 ax-8 2129 ax-9 2136 ax-10 2156 ax-11 2171 ax-12 2184 ax-13 2379 ax-ext 2728 ax-sep 4921 ax-nul 4929 ax-pow 4980 ax-pr 5043 ax-un 7102 ax-cnex 10155 ax-resscn 10156 ax-1cn 10157 ax-icn 10158 ax-addcl 10159 ax-addrcl 10160 ax-mulcl 10161 ax-mulrcl 10162 ax-mulcom 10163 ax-addass 10164 ax-mulass 10165 ax-distr 10166 ax-i2m1 10167 ax-1ne0 10168 ax-1rid 10169 ax-rnegex 10170 ax-rrecex 10171 ax-cnre 10172 ax-pre-lttri 10173 ax-pre-lttrn 10174 ax-pre-ltadd 10175 ax-pre-mulgt0 10176 ax-pre-sup 10177

This theorem depends on definitions: df-bi 197 df-or 384 df-an 385 df-3or 1073 df-3an 1074 df-tru 1623 df-ex 1842 df-nf 1847 df-sb 2035 df-eu 2599 df-mo 2600 df-clab 2735 df-cleq 2741 df-clel 2744 df-nfc 2879 df-ne 2921 df-nel 3024 df-ral 3043 df-rex 3044 df-reu 3045 df-rmo 3046 df-rab 3047 df-v 3330 df-sbc 3565 df-csb 3663 df-dif 3706 df-un 3708 df-in 3710 df-ss 3717 df-nul 4047 df-if 4219 df-pw 4292 df-sn 4310 df-pr 4312 df-op 4316 df-uni 4577 df-br 4793 df-opab 4853 df-mpt 4870 df-id 5162 df-po 5175 df-so 5176 df-xp 5260 df-rel 5261 df-cnv 5262 df-co 5263 df-dm 5264 df-rn 5265 df-res 5266 df-ima 5267 df-iota 6000 df-fun 6039 df-fn 6040 df-f 6041 df-f1 6042 df-fo 6043 df-f1o 6044 df-fv 6045 df-riota 6762 df-ov 6804 df-oprab 6805 df-mpt2 6806 df-er 7899 df-en 8110 df-dom 8111 df-sdom 8112 df-sup 8501 df-pnf 10239 df-mnf 10240 df-xr 10241 df-ltxr 10242 df-le 10243 df-sub 10431 df-neg 10432

This theorem is referenced by: (None)

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