Theorem frinfm 38078

Description: A subset of a well-founded set has an infimum. (Contributed by Jeff Madsen, 2-Sep-2009.)

Assertion

Ref	Expression
frinfm	⊢ ((𝑅 Fr 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)))

Distinct variable groups:   𝑥,𝑅,𝑦,𝑧   𝑥,𝐴,𝑦,𝑧   𝑥,𝐵,𝑦,𝑧   𝑥,𝐶,𝑦

Allowed substitution hint:   𝐶(𝑧)

Proof of Theorem frinfm

Step	Hyp	Ref	Expression
1		fri 5586	. . . . 5 ⊢ (((𝐵 ∈ 𝐶 ∧ 𝑅 Fr 𝐴) ∧ (𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)
2	1	ancom1s 654	. . . 4 ⊢ (((𝑅 Fr 𝐴 ∧ 𝐵 ∈ 𝐶) ∧ (𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)
3	2	exp43 436	. . 3 ⊢ (𝑅 Fr 𝐴 → (𝐵 ∈ 𝐶 → (𝐵 ⊆ 𝐴 → (𝐵 ≠ ∅ → ∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥))))
4	3	3imp2 1351	. 2 ⊢ ((𝑅 Fr 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)
5		ssel2 3917	. . . . . . . 8 ⊢ ((𝐵 ⊆ 𝐴 ∧ 𝑥 ∈ 𝐵) → 𝑥 ∈ 𝐴)
6	5	adantrr 718	. . . . . . 7 ⊢ ((𝐵 ⊆ 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)) → 𝑥 ∈ 𝐴)
7		vex 3434	. . . . . . . . . . . 12 ⊢ 𝑥 ∈ V
8		vex 3434	. . . . . . . . . . . 12 ⊢ 𝑦 ∈ V
9	7, 8	brcnv 5835	. . . . . . . . . . 11 ⊢ (𝑥◡𝑅𝑦 ↔ 𝑦𝑅𝑥)
10	9	biimpi 216	. . . . . . . . . 10 ⊢ (𝑥◡𝑅𝑦 → 𝑦𝑅𝑥)
11	10	con3i 154	. . . . . . . . 9 ⊢ (¬ 𝑦𝑅𝑥 → ¬ 𝑥◡𝑅𝑦)
12	11	ralimi 3075	. . . . . . . 8 ⊢ (∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 → ∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦)
13	12	ad2antll 730	. . . . . . 7 ⊢ ((𝐵 ⊆ 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)) → ∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦)
14		breq2 5090	. . . . . . . . . . 11 ⊢ (𝑧 = 𝑥 → (𝑦◡𝑅𝑧 ↔ 𝑦◡𝑅𝑥))
15	14	rspcev 3565	. . . . . . . . . 10 ⊢ ((𝑥 ∈ 𝐵 ∧ 𝑦◡𝑅𝑥) → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)
16	15	ex 412	. . . . . . . . 9 ⊢ (𝑥 ∈ 𝐵 → (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))
17	16	ralrimivw 3134	. . . . . . . 8 ⊢ (𝑥 ∈ 𝐵 → ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))
18	17	ad2antrl 729	. . . . . . 7 ⊢ ((𝐵 ⊆ 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)) → ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))
19	6, 13, 18	jca32 515	. . . . . 6 ⊢ ((𝐵 ⊆ 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)) → (𝑥 ∈ 𝐴 ∧ (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))))
20	19	ex 412	. . . . 5 ⊢ (𝐵 ⊆ 𝐴 → ((𝑥 ∈ 𝐵 ∧ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥) → (𝑥 ∈ 𝐴 ∧ (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)))))
21	20	reximdv2 3148	. . . 4 ⊢ (𝐵 ⊆ 𝐴 → (∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))))
22	21	adantl 481	. . 3 ⊢ ((𝑅 Fr 𝐴 ∧ 𝐵 ⊆ 𝐴) → (∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))))
23	22	3ad2antr2 1191	. 2 ⊢ ((𝑅 Fr 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → (∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))))
24	4, 23	mpd 15	1 ⊢ ((𝑅 Fr 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 395   ∧ w3a 1087   ∈ wcel 2114   ≠ wne 2933  ∀wral 3052  ∃wrex 3062   ⊆ wss 3890  ∅c0 4274   class class class wbr 5086   Fr wfr 5578  ^◡ccnv 5627

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 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-ext 2709  ax-sep 5232  ax-pr 5374

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-3an 1089  df-tru 1545  df-fal 1555  df-ex 1782  df-sb 2069  df-clab 2716  df-cleq 2729  df-clel 2812  df-ne 2934  df-ral 3053  df-rex 3063  df-rab 3391  df-v 3432  df-dif 3893  df-un 3895  df-in 3897  df-ss 3907  df-nul 4275  df-if 4468  df-pw 4544  df-sn 4569  df-pr 4571  df-op 4575  df-br 5087  df-opab 5149  df-fr 5581  df-cnv 5636

This theorem is referenced by:  welb  38079