supxrgtmnf - Metamath Proof Explorer

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Theorem supxrgtmnf 13307

Description: The supremum of a nonempty set of reals is greater than minus infinity. (Contributed by NM, 2-Feb-2006.)

**Assertion**
Ref	Expression
supxrgtmnf	⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → -∞ < sup(𝐴, ℝ^*, < ))

**Proof of Theorem supxrgtmnf**
Step	Hyp	Ref	Expression
1		supxrbnd 13306	. . . . . 6 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅ ∧ sup(𝐴, ℝ^, < ) < +∞) → sup(𝐴, ℝ^, < ) ∈ ℝ)
2	1	3expia 1121	. . . . 5 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → (sup(𝐴, ℝ^, < ) < +∞ → sup(𝐴, ℝ^, < ) ∈ ℝ))
3	2	con3d 152	. . . 4 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → (¬ sup(𝐴, ℝ^, < ) ∈ ℝ → ¬ sup(𝐴, ℝ^, < ) < +∞))
4		ressxr 11257	. . . . . . . 8 ⊢ ℝ ⊆ ℝ^*
5		sstr 3990	. . . . . . . 8 ⊢ ((𝐴 ⊆ ℝ ∧ ℝ ⊆ ℝ^) → 𝐴 ⊆ ℝ^)
6	4, 5	mpan2 689	. . . . . . 7 ⊢ (𝐴 ⊆ ℝ → 𝐴 ⊆ ℝ^*)
7		supxrcl 13293	. . . . . . 7 ⊢ (𝐴 ⊆ ℝ^* → sup(𝐴, ℝ^, < ) ∈ ℝ^)
8	6, 7	syl 17	. . . . . 6 ⊢ (𝐴 ⊆ ℝ → sup(𝐴, ℝ^, < ) ∈ ℝ^)
9	8	adantr 481	. . . . 5 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → sup(𝐴, ℝ^, < ) ∈ ℝ^)
10		nltpnft 13142	. . . . 5 ⊢ (sup(𝐴, ℝ^, < ) ∈ ℝ^ → (sup(𝐴, ℝ^, < ) = +∞ ↔ ¬ sup(𝐴, ℝ^, < ) < +∞))
11	9, 10	syl 17	. . . 4 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → (sup(𝐴, ℝ^, < ) = +∞ ↔ ¬ sup(𝐴, ℝ^, < ) < +∞))
12	3, 11	sylibrd 258	. . 3 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → (¬ sup(𝐴, ℝ^, < ) ∈ ℝ → sup(𝐴, ℝ^, < ) = +∞))
13	12	orrd 861	. 2 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → (sup(𝐴, ℝ^, < ) ∈ ℝ ∨ sup(𝐴, ℝ^, < ) = +∞))
14		mnfltxr 13106	. 2 ⊢ ((sup(𝐴, ℝ^, < ) ∈ ℝ ∨ sup(𝐴, ℝ^, < ) = +∞) → -∞ < sup(𝐴, ℝ^*, < ))
15	13, 14	syl 17	1 ⊢ ((𝐴 ⊆ ℝ ∧ 𝐴 ≠ ∅) → -∞ < sup(𝐴, ℝ^*, < ))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ wa 396 ∨ wo 845 = wceq 1541 ∈ wcel 2106 ≠ wne 2940 ⊆ wss 3948 ∅c0 4322 class class class wbr 5148 supcsup 9434 ℝcr 11108 +∞cpnf 11244 -∞cmnf 11245 ℝ^*cxr 11246 < clt 11247

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 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 2703 ax-sep 5299 ax-nul 5306 ax-pow 5363 ax-pr 5427 ax-un 7724 ax-cnex 11165 ax-resscn 11166 ax-1cn 11167 ax-icn 11168 ax-addcl 11169 ax-addrcl 11170 ax-mulcl 11171 ax-mulrcl 11172 ax-mulcom 11173 ax-addass 11174 ax-mulass 11175 ax-distr 11176 ax-i2m1 11177 ax-1ne0 11178 ax-1rid 11179 ax-rnegex 11180 ax-rrecex 11181 ax-cnre 11182 ax-pre-lttri 11183 ax-pre-lttrn 11184 ax-pre-ltadd 11185 ax-pre-mulgt0 11186 ax-pre-sup 11187

This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3or 1088 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2534 df-eu 2563 df-clab 2710 df-cleq 2724 df-clel 2810 df-nfc 2885 df-ne 2941 df-nel 3047 df-ral 3062 df-rex 3071 df-rmo 3376 df-reu 3377 df-rab 3433 df-v 3476 df-sbc 3778 df-csb 3894 df-dif 3951 df-un 3953 df-in 3955 df-ss 3965 df-nul 4323 df-if 4529 df-pw 4604 df-sn 4629 df-pr 4631 df-op 4635 df-uni 4909 df-br 5149 df-opab 5211 df-mpt 5232 df-id 5574 df-po 5588 df-so 5589 df-xp 5682 df-rel 5683 df-cnv 5684 df-co 5685 df-dm 5686 df-rn 5687 df-res 5688 df-ima 5689 df-iota 6495 df-fun 6545 df-fn 6546 df-f 6547 df-f1 6548 df-fo 6549 df-f1o 6550 df-fv 6551 df-riota 7364 df-ov 7411 df-oprab 7412 df-mpo 7413 df-er 8702 df-en 8939 df-dom 8940 df-sdom 8941 df-sup 9436 df-pnf 11249 df-mnf 11250 df-xr 11251 df-ltxr 11252 df-le 11253 df-sub 11445 df-neg 11446

This theorem is referenced by: supxrre1 13308 ovolunlem1a 25012 suplesup 44039

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