Mathbox for Thierry Arnoux |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > supxrnemnf | Structured version Visualization version GIF version |
Description: The supremum of a nonempty set of extended reals which does not contain minus infinity is not minus infinity. (Contributed by Thierry Arnoux, 21-Mar-2017.) |
Ref | Expression |
---|---|
supxrnemnf | ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → sup(𝐴, ℝ*, < ) ≠ -∞) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mnfxr 10919 | . . 3 ⊢ -∞ ∈ ℝ* | |
2 | 1 | a1i 11 | . 2 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → -∞ ∈ ℝ*) |
3 | supxrcl 12934 | . . 3 ⊢ (𝐴 ⊆ ℝ* → sup(𝐴, ℝ*, < ) ∈ ℝ*) | |
4 | 3 | 3ad2ant1 1135 | . 2 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → sup(𝐴, ℝ*, < ) ∈ ℝ*) |
5 | simp1 1138 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → 𝐴 ⊆ ℝ*) | |
6 | 5, 1 | jctir 524 | . . 3 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → (𝐴 ⊆ ℝ* ∧ -∞ ∈ ℝ*)) |
7 | simpl 486 | . . . . . . . 8 ⊢ ((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) → 𝐴 ⊆ ℝ*) | |
8 | 7 | sselda 3917 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ ℝ*) |
9 | simpr 488 | . . . . . . . 8 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ 𝐴) | |
10 | simplr 769 | . . . . . . . 8 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → ¬ -∞ ∈ 𝐴) | |
11 | nelneq 2864 | . . . . . . . 8 ⊢ ((𝑥 ∈ 𝐴 ∧ ¬ -∞ ∈ 𝐴) → ¬ 𝑥 = -∞) | |
12 | 9, 10, 11 | syl2anc 587 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → ¬ 𝑥 = -∞) |
13 | ngtmnft 12785 | . . . . . . . . 9 ⊢ (𝑥 ∈ ℝ* → (𝑥 = -∞ ↔ ¬ -∞ < 𝑥)) | |
14 | 13 | biimprd 251 | . . . . . . . 8 ⊢ (𝑥 ∈ ℝ* → (¬ -∞ < 𝑥 → 𝑥 = -∞)) |
15 | 14 | con1d 147 | . . . . . . 7 ⊢ (𝑥 ∈ ℝ* → (¬ 𝑥 = -∞ → -∞ < 𝑥)) |
16 | 8, 12, 15 | sylc 65 | . . . . . 6 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → -∞ < 𝑥) |
17 | 16 | reximdva0 4282 | . . . . 5 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝐴 ≠ ∅) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
18 | 17 | 3impa 1112 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴 ∧ 𝐴 ≠ ∅) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
19 | 18 | 3com23 1128 | . . 3 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
20 | supxrlub 12944 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ -∞ ∈ ℝ*) → (-∞ < sup(𝐴, ℝ*, < ) ↔ ∃𝑥 ∈ 𝐴 -∞ < 𝑥)) | |
21 | 20 | biimprd 251 | . . 3 ⊢ ((𝐴 ⊆ ℝ* ∧ -∞ ∈ ℝ*) → (∃𝑥 ∈ 𝐴 -∞ < 𝑥 → -∞ < sup(𝐴, ℝ*, < ))) |
22 | 6, 19, 21 | sylc 65 | . 2 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → -∞ < sup(𝐴, ℝ*, < )) |
23 | xrltne 12782 | . 2 ⊢ ((-∞ ∈ ℝ* ∧ sup(𝐴, ℝ*, < ) ∈ ℝ* ∧ -∞ < sup(𝐴, ℝ*, < )) → sup(𝐴, ℝ*, < ) ≠ -∞) | |
24 | 2, 4, 22, 23 | syl3anc 1373 | 1 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → sup(𝐴, ℝ*, < ) ≠ -∞) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 399 ∧ w3a 1089 = wceq 1543 ∈ wcel 2112 ≠ wne 2943 ∃wrex 3065 ⊆ wss 3883 ∅c0 4253 class class class wbr 5069 supcsup 9085 -∞cmnf 10894 ℝ*cxr 10895 < clt 10896 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2016 ax-8 2114 ax-9 2122 ax-10 2143 ax-11 2160 ax-12 2177 ax-ext 2710 ax-sep 5208 ax-nul 5215 ax-pow 5274 ax-pr 5338 ax-un 7544 ax-cnex 10814 ax-resscn 10815 ax-1cn 10816 ax-icn 10817 ax-addcl 10818 ax-addrcl 10819 ax-mulcl 10820 ax-mulrcl 10821 ax-mulcom 10822 ax-addass 10823 ax-mulass 10824 ax-distr 10825 ax-i2m1 10826 ax-1ne0 10827 ax-1rid 10828 ax-rnegex 10829 ax-rrecex 10830 ax-cnre 10831 ax-pre-lttri 10832 ax-pre-lttrn 10833 ax-pre-ltadd 10834 ax-pre-mulgt0 10835 ax-pre-sup 10836 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2073 df-mo 2541 df-eu 2570 df-clab 2717 df-cleq 2731 df-clel 2818 df-nfc 2889 df-ne 2944 df-nel 3050 df-ral 3069 df-rex 3070 df-reu 3071 df-rmo 3072 df-rab 3073 df-v 3425 df-sbc 3712 df-csb 3829 df-dif 3886 df-un 3888 df-in 3890 df-ss 3900 df-nul 4254 df-if 4456 df-pw 4531 df-sn 4558 df-pr 4560 df-op 4564 df-uni 4836 df-br 5070 df-opab 5132 df-mpt 5152 df-id 5471 df-po 5485 df-so 5486 df-xp 5574 df-rel 5575 df-cnv 5576 df-co 5577 df-dm 5578 df-rn 5579 df-res 5580 df-ima 5581 df-iota 6358 df-fun 6402 df-fn 6403 df-f 6404 df-f1 6405 df-fo 6406 df-f1o 6407 df-fv 6408 df-riota 7191 df-ov 7237 df-oprab 7238 df-mpo 7239 df-er 8414 df-en 8650 df-dom 8651 df-sdom 8652 df-sup 9087 df-pnf 10898 df-mnf 10899 df-xr 10900 df-ltxr 10901 df-le 10902 df-sub 11093 df-neg 11094 |
This theorem is referenced by: (None) |
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