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Theorem ublbneg 9357
Description: The image under negation of a bounded-above set of reals is bounded below. For a theorem which is similar but also adds that the bounds need to be the tightest possible, see supinfneg 9342. (Contributed by Paul Chapman, 21-Mar-2011.)
Assertion
Ref Expression
ublbneg (∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥 → ∃𝑥 ∈ ℝ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦)
Distinct variable group:   𝑥,𝐴,𝑦,𝑧

Proof of Theorem ublbneg
Dummy variables 𝑎 𝑏 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 breq1 3900 . . . . 5 (𝑏 = 𝑦 → (𝑏𝑎𝑦𝑎))
21cbvralv 2629 . . . 4 (∀𝑏𝐴 𝑏𝑎 ↔ ∀𝑦𝐴 𝑦𝑎)
32rexbii 2417 . . 3 (∃𝑎 ∈ ℝ ∀𝑏𝐴 𝑏𝑎 ↔ ∃𝑎 ∈ ℝ ∀𝑦𝐴 𝑦𝑎)
4 breq2 3901 . . . . 5 (𝑎 = 𝑥 → (𝑦𝑎𝑦𝑥))
54ralbidv 2412 . . . 4 (𝑎 = 𝑥 → (∀𝑦𝐴 𝑦𝑎 ↔ ∀𝑦𝐴 𝑦𝑥))
65cbvrexv 2630 . . 3 (∃𝑎 ∈ ℝ ∀𝑦𝐴 𝑦𝑎 ↔ ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)
73, 6bitri 183 . 2 (∃𝑎 ∈ ℝ ∀𝑏𝐴 𝑏𝑎 ↔ ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)
8 renegcl 7987 . . . 4 (𝑎 ∈ ℝ → -𝑎 ∈ ℝ)
9 elrabi 2808 . . . . . . . . 9 (𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴} → 𝑦 ∈ ℝ)
10 negeq 7919 . . . . . . . . . . . 12 (𝑧 = 𝑦 → -𝑧 = -𝑦)
1110eleq1d 2184 . . . . . . . . . . 11 (𝑧 = 𝑦 → (-𝑧𝐴 ↔ -𝑦𝐴))
1211elrab3 2812 . . . . . . . . . 10 (𝑦 ∈ ℝ → (𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴} ↔ -𝑦𝐴))
1312biimpd 143 . . . . . . . . 9 (𝑦 ∈ ℝ → (𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴} → -𝑦𝐴))
149, 13mpcom 36 . . . . . . . 8 (𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴} → -𝑦𝐴)
15 breq1 3900 . . . . . . . . 9 (𝑏 = -𝑦 → (𝑏𝑎 ↔ -𝑦𝑎))
1615rspcv 2757 . . . . . . . 8 (-𝑦𝐴 → (∀𝑏𝐴 𝑏𝑎 → -𝑦𝑎))
1714, 16syl 14 . . . . . . 7 (𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴} → (∀𝑏𝐴 𝑏𝑎 → -𝑦𝑎))
1817adantl 273 . . . . . 6 ((𝑎 ∈ ℝ ∧ 𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}) → (∀𝑏𝐴 𝑏𝑎 → -𝑦𝑎))
19 lenegcon1 8192 . . . . . . 7 ((𝑎 ∈ ℝ ∧ 𝑦 ∈ ℝ) → (-𝑎𝑦 ↔ -𝑦𝑎))
209, 19sylan2 282 . . . . . 6 ((𝑎 ∈ ℝ ∧ 𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}) → (-𝑎𝑦 ↔ -𝑦𝑎))
2118, 20sylibrd 168 . . . . 5 ((𝑎 ∈ ℝ ∧ 𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}) → (∀𝑏𝐴 𝑏𝑎 → -𝑎𝑦))
2221ralrimdva 2487 . . . 4 (𝑎 ∈ ℝ → (∀𝑏𝐴 𝑏𝑎 → ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}-𝑎𝑦))
23 breq1 3900 . . . . . 6 (𝑥 = -𝑎 → (𝑥𝑦 ↔ -𝑎𝑦))
2423ralbidv 2412 . . . . 5 (𝑥 = -𝑎 → (∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦 ↔ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}-𝑎𝑦))
2524rspcev 2761 . . . 4 ((-𝑎 ∈ ℝ ∧ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}-𝑎𝑦) → ∃𝑥 ∈ ℝ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦)
268, 22, 25syl6an 1393 . . 3 (𝑎 ∈ ℝ → (∀𝑏𝐴 𝑏𝑎 → ∃𝑥 ∈ ℝ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦))
2726rexlimiv 2518 . 2 (∃𝑎 ∈ ℝ ∀𝑏𝐴 𝑏𝑎 → ∃𝑥 ∈ ℝ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦)
287, 27sylbir 134 1 (∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥 → ∃𝑥 ∈ ℝ ∀𝑦 ∈ {𝑧 ∈ ℝ ∣ -𝑧𝐴}𝑥𝑦)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103  wb 104   = wceq 1314  wcel 1463  wral 2391  wrex 2392  {crab 2395   class class class wbr 3897  cr 7583  cle 7765  -cneg 7898
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 586  ax-in2 587  ax-io 681  ax-5 1406  ax-7 1407  ax-gen 1408  ax-ie1 1452  ax-ie2 1453  ax-8 1465  ax-10 1466  ax-11 1467  ax-i12 1468  ax-bndl 1469  ax-4 1470  ax-13 1474  ax-14 1475  ax-17 1489  ax-i9 1493  ax-ial 1497  ax-i5r 1498  ax-ext 2097  ax-sep 4014  ax-pow 4066  ax-pr 4099  ax-un 4323  ax-setind 4420  ax-cnex 7675  ax-resscn 7676  ax-1cn 7677  ax-1re 7678  ax-icn 7679  ax-addcl 7680  ax-addrcl 7681  ax-mulcl 7682  ax-addcom 7684  ax-addass 7686  ax-distr 7688  ax-i2m1 7689  ax-0id 7692  ax-rnegex 7693  ax-cnre 7695  ax-pre-ltadd 7700
This theorem depends on definitions:  df-bi 116  df-3an 947  df-tru 1317  df-fal 1320  df-nf 1420  df-sb 1719  df-eu 1978  df-mo 1979  df-clab 2102  df-cleq 2108  df-clel 2111  df-nfc 2245  df-ne 2284  df-nel 2379  df-ral 2396  df-rex 2397  df-reu 2398  df-rab 2400  df-v 2660  df-sbc 2881  df-dif 3041  df-un 3043  df-in 3045  df-ss 3052  df-pw 3480  df-sn 3501  df-pr 3502  df-op 3504  df-uni 3705  df-br 3898  df-opab 3958  df-id 4183  df-xp 4513  df-rel 4514  df-cnv 4515  df-co 4516  df-dm 4517  df-iota 5056  df-fun 5093  df-fv 5099  df-riota 5696  df-ov 5743  df-oprab 5744  df-mpo 5745  df-pnf 7766  df-mnf 7767  df-xr 7768  df-ltxr 7769  df-le 7770  df-sub 7899  df-neg 7900
This theorem is referenced by: (None)
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