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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 10498 | . . 3 ⊢ -∞ ∈ ℝ* | |
2 | 1 | a1i 11 | . 2 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → -∞ ∈ ℝ*) |
3 | supxrcl 12524 | . . 3 ⊢ (𝐴 ⊆ ℝ* → sup(𝐴, ℝ*, < ) ∈ ℝ*) | |
4 | 3 | 3ad2ant1 1113 | . 2 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → sup(𝐴, ℝ*, < ) ∈ ℝ*) |
5 | simp1 1116 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → 𝐴 ⊆ ℝ*) | |
6 | 5, 1 | jctir 513 | . . 3 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → (𝐴 ⊆ ℝ* ∧ -∞ ∈ ℝ*)) |
7 | simpl 475 | . . . . . . . 8 ⊢ ((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) → 𝐴 ⊆ ℝ*) | |
8 | 7 | sselda 3859 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ ℝ*) |
9 | simpr 477 | . . . . . . . 8 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ 𝐴) | |
10 | simplr 756 | . . . . . . . 8 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → ¬ -∞ ∈ 𝐴) | |
11 | nelneq 2891 | . . . . . . . 8 ⊢ ((𝑥 ∈ 𝐴 ∧ ¬ -∞ ∈ 𝐴) → ¬ 𝑥 = -∞) | |
12 | 9, 10, 11 | syl2anc 576 | . . . . . . 7 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → ¬ 𝑥 = -∞) |
13 | ngtmnft 12376 | . . . . . . . . 9 ⊢ (𝑥 ∈ ℝ* → (𝑥 = -∞ ↔ ¬ -∞ < 𝑥)) | |
14 | 13 | biimprd 240 | . . . . . . . 8 ⊢ (𝑥 ∈ ℝ* → (¬ -∞ < 𝑥 → 𝑥 = -∞)) |
15 | 14 | con1d 142 | . . . . . . 7 ⊢ (𝑥 ∈ ℝ* → (¬ 𝑥 = -∞ → -∞ < 𝑥)) |
16 | 8, 12, 15 | sylc 65 | . . . . . 6 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝑥 ∈ 𝐴) → -∞ < 𝑥) |
17 | 16 | reximdva0 4199 | . . . . 5 ⊢ (((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴) ∧ 𝐴 ≠ ∅) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
18 | 17 | 3impa 1090 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ ¬ -∞ ∈ 𝐴 ∧ 𝐴 ≠ ∅) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
19 | 18 | 3com23 1106 | . . 3 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → ∃𝑥 ∈ 𝐴 -∞ < 𝑥) |
20 | supxrlub 12534 | . . . 4 ⊢ ((𝐴 ⊆ ℝ* ∧ -∞ ∈ ℝ*) → (-∞ < sup(𝐴, ℝ*, < ) ↔ ∃𝑥 ∈ 𝐴 -∞ < 𝑥)) | |
21 | 20 | biimprd 240 | . . 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 12373 | . 2 ⊢ ((-∞ ∈ ℝ* ∧ sup(𝐴, ℝ*, < ) ∈ ℝ* ∧ -∞ < sup(𝐴, ℝ*, < )) → sup(𝐴, ℝ*, < ) ≠ -∞) | |
24 | 2, 4, 22, 23 | syl3anc 1351 | 1 ⊢ ((𝐴 ⊆ ℝ* ∧ 𝐴 ≠ ∅ ∧ ¬ -∞ ∈ 𝐴) → sup(𝐴, ℝ*, < ) ≠ -∞) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 387 ∧ w3a 1068 = wceq 1507 ∈ wcel 2050 ≠ wne 2968 ∃wrex 3090 ⊆ wss 3830 ∅c0 4179 class class class wbr 4929 supcsup 8699 -∞cmnf 10472 ℝ*cxr 10473 < clt 10474 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1758 ax-4 1772 ax-5 1869 ax-6 1928 ax-7 1965 ax-8 2052 ax-9 2059 ax-10 2079 ax-11 2093 ax-12 2106 ax-13 2301 ax-ext 2751 ax-sep 5060 ax-nul 5067 ax-pow 5119 ax-pr 5186 ax-un 7279 ax-cnex 10391 ax-resscn 10392 ax-1cn 10393 ax-icn 10394 ax-addcl 10395 ax-addrcl 10396 ax-mulcl 10397 ax-mulrcl 10398 ax-mulcom 10399 ax-addass 10400 ax-mulass 10401 ax-distr 10402 ax-i2m1 10403 ax-1ne0 10404 ax-1rid 10405 ax-rnegex 10406 ax-rrecex 10407 ax-cnre 10408 ax-pre-lttri 10409 ax-pre-lttrn 10410 ax-pre-ltadd 10411 ax-pre-mulgt0 10412 ax-pre-sup 10413 |
This theorem depends on definitions: df-bi 199 df-an 388 df-or 834 df-3or 1069 df-3an 1070 df-tru 1510 df-ex 1743 df-nf 1747 df-sb 2016 df-mo 2547 df-eu 2584 df-clab 2760 df-cleq 2772 df-clel 2847 df-nfc 2919 df-ne 2969 df-nel 3075 df-ral 3094 df-rex 3095 df-reu 3096 df-rmo 3097 df-rab 3098 df-v 3418 df-sbc 3683 df-csb 3788 df-dif 3833 df-un 3835 df-in 3837 df-ss 3844 df-nul 4180 df-if 4351 df-pw 4424 df-sn 4442 df-pr 4444 df-op 4448 df-uni 4713 df-br 4930 df-opab 4992 df-mpt 5009 df-id 5312 df-po 5326 df-so 5327 df-xp 5413 df-rel 5414 df-cnv 5415 df-co 5416 df-dm 5417 df-rn 5418 df-res 5419 df-ima 5420 df-iota 6152 df-fun 6190 df-fn 6191 df-f 6192 df-f1 6193 df-fo 6194 df-f1o 6195 df-fv 6196 df-riota 6937 df-ov 6979 df-oprab 6980 df-mpo 6981 df-er 8089 df-en 8307 df-dom 8308 df-sdom 8309 df-sup 8701 df-pnf 10476 df-mnf 10477 df-xr 10478 df-ltxr 10479 df-le 10480 df-sub 10672 df-neg 10673 |
This theorem is referenced by: (None) |
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