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Theorem infssd 32728
Description: Inequality deduction for infimum of a subset. (Contributed by AV, 4-Oct-2020.)
Hypotheses
Ref Expression
infssd.0 (𝜑𝑅 Or 𝐴)
infssd.1 (𝜑𝐶𝐵)
infssd.3 (𝜑 → ∃𝑥𝐴 (∀𝑦𝐶 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦𝐴 (𝑥𝑅𝑦 → ∃𝑧𝐶 𝑧𝑅𝑦)))
infssd.4 (𝜑 → ∃𝑥𝐴 (∀𝑦𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦𝐴 (𝑥𝑅𝑦 → ∃𝑧𝐵 𝑧𝑅𝑦)))
Assertion
Ref Expression
infssd (𝜑 → ¬ inf(𝐶, 𝐴, 𝑅)𝑅inf(𝐵, 𝐴, 𝑅))
Distinct variable groups:   𝑥,𝑦,𝑧,𝐴   𝑥,𝐵,𝑦,𝑧   𝑥,𝐶,𝑦,𝑧   𝑥,𝑅,𝑦,𝑧   𝜑,𝑧
Allowed substitution hints:   𝜑(𝑥,𝑦)

Proof of Theorem infssd
StepHypRef Expression
1 infssd.0 . . 3 (𝜑𝑅 Or 𝐴)
2 infssd.4 . . 3 (𝜑 → ∃𝑥𝐴 (∀𝑦𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦𝐴 (𝑥𝑅𝑦 → ∃𝑧𝐵 𝑧𝑅𝑦)))
31, 2infcl 9526 . 2 (𝜑 → inf(𝐵, 𝐴, 𝑅) ∈ 𝐴)
4 infssd.1 . . . . 5 (𝜑𝐶𝐵)
54sseld 3994 . . . 4 (𝜑 → (𝑧𝐶𝑧𝐵))
61, 2inflb 9527 . . . 4 (𝜑 → (𝑧𝐵 → ¬ 𝑧𝑅inf(𝐵, 𝐴, 𝑅)))
75, 6syld 47 . . 3 (𝜑 → (𝑧𝐶 → ¬ 𝑧𝑅inf(𝐵, 𝐴, 𝑅)))
87ralrimiv 3143 . 2 (𝜑 → ∀𝑧𝐶 ¬ 𝑧𝑅inf(𝐵, 𝐴, 𝑅))
9 infssd.3 . . 3 (𝜑 → ∃𝑥𝐴 (∀𝑦𝐶 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦𝐴 (𝑥𝑅𝑦 → ∃𝑧𝐶 𝑧𝑅𝑦)))
101, 9infnlb 9530 . 2 (𝜑 → ((inf(𝐵, 𝐴, 𝑅) ∈ 𝐴 ∧ ∀𝑧𝐶 ¬ 𝑧𝑅inf(𝐵, 𝐴, 𝑅)) → ¬ inf(𝐶, 𝐴, 𝑅)𝑅inf(𝐵, 𝐴, 𝑅)))
113, 8, 10mp2and 699 1 (𝜑 → ¬ inf(𝐶, 𝐴, 𝑅)𝑅inf(𝐵, 𝐴, 𝑅))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wa 395  wcel 2106  wral 3059  wrex 3068  wss 3963   class class class wbr 5148   Or wor 5596  infcinf 9479
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pr 5438
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-rmo 3378  df-reu 3379  df-rab 3434  df-v 3480  df-sbc 3792  df-dif 3966  df-un 3968  df-ss 3980  df-nul 4340  df-if 4532  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-br 5149  df-opab 5211  df-po 5597  df-so 5598  df-cnv 5697  df-iota 6516  df-riota 7388  df-sup 9480  df-inf 9481
This theorem is referenced by:  xrge0infssd  32772
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