Theorem psssdm2 17038

Description: Field of a subposet. (Contributed by Mario Carneiro, 9-Sep-2015.)

Hypothesis

Ref	Expression
psssdm.1	⊢ 𝑋 = dom 𝑅

Assertion

Ref	Expression
psssdm2	⊢ (𝑅 ∈ PosetRel → dom (𝑅 ∩ (𝐴 × 𝐴)) = (𝑋 ∩ 𝐴))

Proof of Theorem psssdm2

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		dmin 5254	. . . 4 ⊢ dom (𝑅 ∩ (𝐴 × 𝐴)) ⊆ (dom 𝑅 ∩ dom (𝐴 × 𝐴))
2		psssdm.1	. . . . . 6 ⊢ 𝑋 = dom 𝑅
3	2	eqcomi 2619	. . . . 5 ⊢ dom 𝑅 = 𝑋
4		dmxpid 5266	. . . . 5 ⊢ dom (𝐴 × 𝐴) = 𝐴
5	3, 4	ineq12i 3774	. . . 4 ⊢ (dom 𝑅 ∩ dom (𝐴 × 𝐴)) = (𝑋 ∩ 𝐴)
6	1, 5	sseqtri 3600	. . 3 ⊢ dom (𝑅 ∩ (𝐴 × 𝐴)) ⊆ (𝑋 ∩ 𝐴)
7	6	a1i 11	. 2 ⊢ (𝑅 ∈ PosetRel → dom (𝑅 ∩ (𝐴 × 𝐴)) ⊆ (𝑋 ∩ 𝐴))
8		inss2 3796	. . . . . . 7 ⊢ (𝑋 ∩ 𝐴) ⊆ 𝐴
9		simpr 476	. . . . . . 7 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ (𝑋 ∩ 𝐴)) → 𝑥 ∈ (𝑋 ∩ 𝐴))
10	8, 9	sseldi 3566	. . . . . 6 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ (𝑋 ∩ 𝐴)) → 𝑥 ∈ 𝐴)
11		inss1 3795	. . . . . . . 8 ⊢ (𝑋 ∩ 𝐴) ⊆ 𝑋
12	11	sseli 3564	. . . . . . 7 ⊢ (𝑥 ∈ (𝑋 ∩ 𝐴) → 𝑥 ∈ 𝑋)
13	2	psref 17031	. . . . . . 7 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ 𝑋) → 𝑥𝑅𝑥)
14	12, 13	sylan2 490	. . . . . 6 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ (𝑋 ∩ 𝐴)) → 𝑥𝑅𝑥)
15		brinxp2 5103	. . . . . 6 ⊢ (𝑥(𝑅 ∩ (𝐴 × 𝐴))𝑥 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴 ∧ 𝑥𝑅𝑥))
16	10, 10, 14, 15	syl3anbrc 1239	. . . . 5 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ (𝑋 ∩ 𝐴)) → 𝑥(𝑅 ∩ (𝐴 × 𝐴))𝑥)
17		vex 3176	. . . . . 6 ⊢ 𝑥 ∈ V
18	17, 17	breldm 5251	. . . . 5 ⊢ (𝑥(𝑅 ∩ (𝐴 × 𝐴))𝑥 → 𝑥 ∈ dom (𝑅 ∩ (𝐴 × 𝐴)))
19	16, 18	syl 17	. . . 4 ⊢ ((𝑅 ∈ PosetRel ∧ 𝑥 ∈ (𝑋 ∩ 𝐴)) → 𝑥 ∈ dom (𝑅 ∩ (𝐴 × 𝐴)))
20	19	ex 449	. . 3 ⊢ (𝑅 ∈ PosetRel → (𝑥 ∈ (𝑋 ∩ 𝐴) → 𝑥 ∈ dom (𝑅 ∩ (𝐴 × 𝐴))))
21	20	ssrdv 3574	. 2 ⊢ (𝑅 ∈ PosetRel → (𝑋 ∩ 𝐴) ⊆ dom (𝑅 ∩ (𝐴 × 𝐴)))
22	7, 21	eqssd 3585	1 ⊢ (𝑅 ∈ PosetRel → dom (𝑅 ∩ (𝐴 × 𝐴)) = (𝑋 ∩ 𝐴))

Syntax hints:   → wi 4   ∧ wa 383   = wceq 1475   ∈ wcel 1977   ∩ cin 3539   ⊆ wss 3540   class class class wbr 4583   × cxp 5036  dom cdm 5038  PosetRelcps 17021

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-sep 4709  ax-nul 4717  ax-pr 4833

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3an 1033  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-mo 2463  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ne 2782  df-ral 2901  df-rex 2902  df-rab 2905  df-v 3175  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-nul 3875  df-if 4037  df-sn 4126  df-pr 4128  df-op 4132  df-uni 4373  df-br 4584  df-opab 4644  df-id 4953  df-xp 5044  df-rel 5045  df-cnv 5046  df-co 5047  df-dm 5048  df-rn 5049  df-res 5050  df-ps 17023

This theorem is referenced by:  psssdm  17039  ordtrest  20816