Theorem onfrALTlem3 41250

Description: Lemma for onfrALT 41255. (Contributed by Alan Sare, 22-Jul-2012.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
onfrALTlem3	⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ∃𝑦 ∈ (𝑎 ∩ 𝑥)((𝑎 ∩ 𝑥) ∩ 𝑦) = ∅))

Distinct variable groups:   𝑦,𝑎   𝑥,𝑦

Proof of Theorem onfrALTlem3

Dummy variable 𝑏 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		ssid 3937	. . 3 ⊢ (𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥)
2		simpr 488	. . . . 5 ⊢ ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ¬ (𝑎 ∩ 𝑥) = ∅)
3	2	a1i 11	. . . 4 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ¬ (𝑎 ∩ 𝑥) = ∅))
4		df-ne 2988	. . . 4 ⊢ ((𝑎 ∩ 𝑥) ≠ ∅ ↔ ¬ (𝑎 ∩ 𝑥) = ∅)
5	3, 4	syl6ibr 255	. . 3 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → (𝑎 ∩ 𝑥) ≠ ∅))
6		pm3.2 473	. . 3 ⊢ ((𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥) → ((𝑎 ∩ 𝑥) ≠ ∅ → ((𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥) ∧ (𝑎 ∩ 𝑥) ≠ ∅)))
7	1, 5, 6	mpsylsyld 69	. 2 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ((𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥) ∧ (𝑎 ∩ 𝑥) ≠ ∅)))
8		vex 3444	. . . . 5 ⊢ 𝑥 ∈ V
9	8	inex2 5186	. . . 4 ⊢ (𝑎 ∩ 𝑥) ∈ V
10		inss2 4156	. . . . . . 7 ⊢ (𝑎 ∩ 𝑥) ⊆ 𝑥
11		simpl 486	. . . . . . . . . 10 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → 𝑎 ⊆ On)
12		simpl 486	. . . . . . . . . 10 ⊢ ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → 𝑥 ∈ 𝑎)
13		ssel 3908	. . . . . . . . . 10 ⊢ (𝑎 ⊆ On → (𝑥 ∈ 𝑎 → 𝑥 ∈ On))
14	11, 12, 13	syl2im 40	. . . . . . . . 9 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → 𝑥 ∈ On))
15		eloni 6169	. . . . . . . . 9 ⊢ (𝑥 ∈ On → Ord 𝑥)
16	14, 15	syl6 35	. . . . . . . 8 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → Ord 𝑥))
17		ordwe 6172	. . . . . . . 8 ⊢ (Ord 𝑥 → E We 𝑥)
18	16, 17	syl6 35	. . . . . . 7 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → E We 𝑥))
19		wess 5506	. . . . . . 7 ⊢ ((𝑎 ∩ 𝑥) ⊆ 𝑥 → ( E We 𝑥 → E We (𝑎 ∩ 𝑥)))
20	10, 18, 19	mpsylsyld 69	. . . . . 6 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → E We (𝑎 ∩ 𝑥)))
21		wefr 5509	. . . . . 6 ⊢ ( E We (𝑎 ∩ 𝑥) → E Fr (𝑎 ∩ 𝑥))
22	20, 21	syl6 35	. . . . 5 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → E Fr (𝑎 ∩ 𝑥)))
23		dfepfr 5504	. . . . 5 ⊢ ( E Fr (𝑎 ∩ 𝑥) ↔ ∀𝑏((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅))
24	22, 23	syl6ib 254	. . . 4 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ∀𝑏((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅)))
25		spsbc 3733	. . . 4 ⊢ ((𝑎 ∩ 𝑥) ∈ V → (∀𝑏((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅) → [(𝑎 ∩ 𝑥) / 𝑏]((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅)))
26	9, 24, 25	mpsylsyld 69	. . 3 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → [(𝑎 ∩ 𝑥) / 𝑏]((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅)))
27		onfrALTlem5 41248	. . 3 ⊢ ([(𝑎 ∩ 𝑥) / 𝑏]((𝑏 ⊆ (𝑎 ∩ 𝑥) ∧ 𝑏 ≠ ∅) → ∃𝑦 ∈ 𝑏 (𝑏 ∩ 𝑦) = ∅) ↔ (((𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥) ∧ (𝑎 ∩ 𝑥) ≠ ∅) → ∃𝑦 ∈ (𝑎 ∩ 𝑥)((𝑎 ∩ 𝑥) ∩ 𝑦) = ∅))
28	26, 27	syl6ib 254	. 2 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → (((𝑎 ∩ 𝑥) ⊆ (𝑎 ∩ 𝑥) ∧ (𝑎 ∩ 𝑥) ≠ ∅) → ∃𝑦 ∈ (𝑎 ∩ 𝑥)((𝑎 ∩ 𝑥) ∩ 𝑦) = ∅)))
29	7, 28	mpdd 43	1 ⊢ ((𝑎 ⊆ On ∧ 𝑎 ≠ ∅) → ((𝑥 ∈ 𝑎 ∧ ¬ (𝑎 ∩ 𝑥) = ∅) → ∃𝑦 ∈ (𝑎 ∩ 𝑥)((𝑎 ∩ 𝑥) ∩ 𝑦) = ∅))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 399  ∀wal 1536   = wceq 1538   ∈ wcel 2111   ≠ wne 2987  ∃wrex 3107  Vcvv 3441  [wsbc 3720   ∩ cin 3880   ⊆ wss 3881  ∅c0 4243   E cep 5429   Fr wfr 5475   We wwe 5477  Ord word 6158  Oncon0 6159

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 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770  ax-sep 5167  ax-nul 5174  ax-pr 5295

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1086  df-tru 1541  df-fal 1551  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2598  df-eu 2629  df-clab 2777  df-cleq 2791  df-clel 2870  df-nfc 2938  df-ne 2988  df-ral 3111  df-rex 3112  df-rab 3115  df-v 3443  df-sbc 3721  df-csb 3829  df-dif 3884  df-un 3886  df-in 3888  df-ss 3898  df-nul 4244  df-if 4426  df-sn 4526  df-pr 4528  df-op 4532  df-uni 4801  df-br 5031  df-opab 5093  df-tr 5137  df-eprel 5430  df-po 5438  df-so 5439  df-fr 5478  df-we 5480  df-ord 6162  df-on 6163

This theorem is referenced by:  onfrALTlem2  41252