Theorem fin23lem24 10317

Description: Lemma for fin23 10384. In a class of ordinals, each element is fully identified by those of its predecessors which also belong to the class. (Contributed by Stefan O'Rear, 1-Nov-2014.)

Assertion

Ref	Expression
fin23lem24	⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ∩ 𝐵) = (𝐷 ∩ 𝐵) ↔ 𝐶 = 𝐷))

Proof of Theorem fin23lem24

Step	Hyp	Ref	Expression
1		simpll 766	. . . . . 6 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → Ord 𝐴)
2		simplr 768	. . . . . . 7 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → 𝐵 ⊆ 𝐴)
3		simprl 770	. . . . . . 7 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → 𝐶 ∈ 𝐵)
4	2, 3	sseldd 3984	. . . . . 6 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → 𝐶 ∈ 𝐴)
5		ordelord 6387	. . . . . 6 ⊢ ((Ord 𝐴 ∧ 𝐶 ∈ 𝐴) → Ord 𝐶)
6	1, 4, 5	syl2anc 585	. . . . 5 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → Ord 𝐶)
7		simprr 772	. . . . . . 7 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → 𝐷 ∈ 𝐵)
8	2, 7	sseldd 3984	. . . . . 6 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → 𝐷 ∈ 𝐴)
9		ordelord 6387	. . . . . 6 ⊢ ((Ord 𝐴 ∧ 𝐷 ∈ 𝐴) → Ord 𝐷)
10	1, 8, 9	syl2anc 585	. . . . 5 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → Ord 𝐷)
11		ordtri3 6401	. . . . . 6 ⊢ ((Ord 𝐶 ∧ Ord 𝐷) → (𝐶 = 𝐷 ↔ ¬ (𝐶 ∈ 𝐷 ∨ 𝐷 ∈ 𝐶)))
12	11	necon2abid 2984	. . . . 5 ⊢ ((Ord 𝐶 ∧ Ord 𝐷) → ((𝐶 ∈ 𝐷 ∨ 𝐷 ∈ 𝐶) ↔ 𝐶 ≠ 𝐷))
13	6, 10, 12	syl2anc 585	. . . 4 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ∈ 𝐷 ∨ 𝐷 ∈ 𝐶) ↔ 𝐶 ≠ 𝐷))
14		simpr 486	. . . . . . . . 9 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → 𝐶 ∈ 𝐷)
15		simplrl 776	. . . . . . . . 9 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → 𝐶 ∈ 𝐵)
16	14, 15	elind 4195	. . . . . . . 8 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → 𝐶 ∈ (𝐷 ∩ 𝐵))
17	6	adantr 482	. . . . . . . . . 10 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → Ord 𝐶)
18		ordirr 6383	. . . . . . . . . 10 ⊢ (Ord 𝐶 → ¬ 𝐶 ∈ 𝐶)
19	17, 18	syl 17	. . . . . . . . 9 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → ¬ 𝐶 ∈ 𝐶)
20		elinel1 4196	. . . . . . . . 9 ⊢ (𝐶 ∈ (𝐶 ∩ 𝐵) → 𝐶 ∈ 𝐶)
21	19, 20	nsyl 140	. . . . . . . 8 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → ¬ 𝐶 ∈ (𝐶 ∩ 𝐵))
22		nelne1 3040	. . . . . . . 8 ⊢ ((𝐶 ∈ (𝐷 ∩ 𝐵) ∧ ¬ 𝐶 ∈ (𝐶 ∩ 𝐵)) → (𝐷 ∩ 𝐵) ≠ (𝐶 ∩ 𝐵))
23	16, 21, 22	syl2anc 585	. . . . . . 7 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → (𝐷 ∩ 𝐵) ≠ (𝐶 ∩ 𝐵))
24	23	necomd 2997	. . . . . 6 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐶 ∈ 𝐷) → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵))
25		simpr 486	. . . . . . . 8 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → 𝐷 ∈ 𝐶)
26		simplrr 777	. . . . . . . 8 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → 𝐷 ∈ 𝐵)
27	25, 26	elind 4195	. . . . . . 7 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → 𝐷 ∈ (𝐶 ∩ 𝐵))
28	10	adantr 482	. . . . . . . . 9 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → Ord 𝐷)
29		ordirr 6383	. . . . . . . . 9 ⊢ (Ord 𝐷 → ¬ 𝐷 ∈ 𝐷)
30	28, 29	syl 17	. . . . . . . 8 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → ¬ 𝐷 ∈ 𝐷)
31		elinel1 4196	. . . . . . . 8 ⊢ (𝐷 ∈ (𝐷 ∩ 𝐵) → 𝐷 ∈ 𝐷)
32	30, 31	nsyl 140	. . . . . . 7 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → ¬ 𝐷 ∈ (𝐷 ∩ 𝐵))
33		nelne1 3040	. . . . . . 7 ⊢ ((𝐷 ∈ (𝐶 ∩ 𝐵) ∧ ¬ 𝐷 ∈ (𝐷 ∩ 𝐵)) → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵))
34	27, 32, 33	syl2anc 585	. . . . . 6 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ 𝐷 ∈ 𝐶) → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵))
35	24, 34	jaodan 957	. . . . 5 ⊢ ((((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) ∧ (𝐶 ∈ 𝐷 ∨ 𝐷 ∈ 𝐶)) → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵))
36	35	ex 414	. . . 4 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ∈ 𝐷 ∨ 𝐷 ∈ 𝐶) → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵)))
37	13, 36	sylbird 260	. . 3 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → (𝐶 ≠ 𝐷 → (𝐶 ∩ 𝐵) ≠ (𝐷 ∩ 𝐵)))
38	37	necon4d 2965	. 2 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ∩ 𝐵) = (𝐷 ∩ 𝐵) → 𝐶 = 𝐷))
39		ineq1 4206	. 2 ⊢ (𝐶 = 𝐷 → (𝐶 ∩ 𝐵) = (𝐷 ∩ 𝐵))
40	38, 39	impbid1 224	1 ⊢ (((Ord 𝐴 ∧ 𝐵 ⊆ 𝐴) ∧ (𝐶 ∈ 𝐵 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ∩ 𝐵) = (𝐷 ∩ 𝐵) ↔ 𝐶 = 𝐷))

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 205   ∧ wa 397   ∨ wo 846   = wceq 1542   ∈ wcel 2107   ≠ wne 2941   ∩ cin 3948   ⊆ wss 3949  Ord word 6364

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-ext 2704  ax-sep 5300  ax-nul 5307  ax-pr 5428

This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3or 1089  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-sb 2069  df-clab 2711  df-cleq 2725  df-clel 2811  df-ne 2942  df-ral 3063  df-rex 3072  df-rab 3434  df-v 3477  df-dif 3952  df-un 3954  df-in 3956  df-ss 3966  df-pss 3968  df-nul 4324  df-if 4530  df-pw 4605  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4910  df-br 5150  df-opab 5212  df-tr 5267  df-eprel 5581  df-po 5589  df-so 5590  df-fr 5632  df-we 5634  df-ord 6368

This theorem is referenced by:  fin23lem23  10321