Theorem difelsiga 29523

Description: A sigma-algebra is closed under class differences. (Contributed by Thierry Arnoux, 13-Sep-2016.)

Assertion

Ref	Expression
difelsiga	⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (𝐴 ∖ 𝐵) ∈ 𝑆)

Proof of Theorem difelsiga

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		simp2 1055	. . . 4 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → 𝐴 ∈ 𝑆)
2		elssuni 4403	. . . 4 ⊢ (𝐴 ∈ 𝑆 → 𝐴 ⊆ ∪ 𝑆)
3		difin2 3849	. . . 4 ⊢ (𝐴 ⊆ ∪ 𝑆 → (𝐴 ∖ 𝐵) = ((∪ 𝑆 ∖ 𝐵) ∩ 𝐴))
4	1, 2, 3	3syl 18	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (𝐴 ∖ 𝐵) = ((∪ 𝑆 ∖ 𝐵) ∩ 𝐴))
5		isrnsigau 29517	. . . . . . . 8 ⊢ (𝑆 ∈ ∪ ran sigAlgebra → (𝑆 ⊆ 𝒫 ∪ 𝑆 ∧ (∪ 𝑆 ∈ 𝑆 ∧ ∀𝑥 ∈ 𝑆 (∪ 𝑆 ∖ 𝑥) ∈ 𝑆 ∧ ∀𝑥 ∈ 𝒫 𝑆(𝑥 ≼ ω → ∪ 𝑥 ∈ 𝑆))))
6	5	simprd 478	. . . . . . 7 ⊢ (𝑆 ∈ ∪ ran sigAlgebra → (∪ 𝑆 ∈ 𝑆 ∧ ∀𝑥 ∈ 𝑆 (∪ 𝑆 ∖ 𝑥) ∈ 𝑆 ∧ ∀𝑥 ∈ 𝒫 𝑆(𝑥 ≼ ω → ∪ 𝑥 ∈ 𝑆)))
7	6	simp2d 1067	. . . . . 6 ⊢ (𝑆 ∈ ∪ ran sigAlgebra → ∀𝑥 ∈ 𝑆 (∪ 𝑆 ∖ 𝑥) ∈ 𝑆)
8		difeq2 3684	. . . . . . . 8 ⊢ (𝑥 = 𝐵 → (∪ 𝑆 ∖ 𝑥) = (∪ 𝑆 ∖ 𝐵))
9	8	eleq1d 2672	. . . . . . 7 ⊢ (𝑥 = 𝐵 → ((∪ 𝑆 ∖ 𝑥) ∈ 𝑆 ↔ (∪ 𝑆 ∖ 𝐵) ∈ 𝑆))
10	9	rspccva 3281	. . . . . 6 ⊢ ((∀𝑥 ∈ 𝑆 (∪ 𝑆 ∖ 𝑥) ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (∪ 𝑆 ∖ 𝐵) ∈ 𝑆)
11	7, 10	sylan 487	. . . . 5 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐵 ∈ 𝑆) → (∪ 𝑆 ∖ 𝐵) ∈ 𝑆)
12	11	3adant2 1073	. . . 4 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (∪ 𝑆 ∖ 𝐵) ∈ 𝑆)
13		intprg 4446	. . . 4 ⊢ (((∪ 𝑆 ∖ 𝐵) ∈ 𝑆 ∧ 𝐴 ∈ 𝑆) → ∩ {(∪ 𝑆 ∖ 𝐵), 𝐴} = ((∪ 𝑆 ∖ 𝐵) ∩ 𝐴))
14	12, 1, 13	syl2anc 691	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → ∩ {(∪ 𝑆 ∖ 𝐵), 𝐴} = ((∪ 𝑆 ∖ 𝐵) ∩ 𝐴))
15	4, 14	eqtr4d 2647	. 2 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (𝐴 ∖ 𝐵) = ∩ {(∪ 𝑆 ∖ 𝐵), 𝐴})
16		simp1 1054	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → 𝑆 ∈ ∪ ran sigAlgebra)
17		prssi 4293	. . . . 5 ⊢ (((∪ 𝑆 ∖ 𝐵) ∈ 𝑆 ∧ 𝐴 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ⊆ 𝑆)
18	12, 1, 17	syl2anc 691	. . . 4 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ⊆ 𝑆)
19		prex 4836	. . . . 5 ⊢ {(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ V
20	19	elpw 4114	. . . 4 ⊢ ({(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ 𝒫 𝑆 ↔ {(∪ 𝑆 ∖ 𝐵), 𝐴} ⊆ 𝑆)
21	18, 20	sylibr 223	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ 𝒫 𝑆)
22		prct 28875	. . . 4 ⊢ (((∪ 𝑆 ∖ 𝐵) ∈ 𝑆 ∧ 𝐴 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ≼ ω)
23	12, 1, 22	syl2anc 691	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ≼ ω)
24		prnzg 4254	. . . 4 ⊢ ((∪ 𝑆 ∖ 𝐵) ∈ 𝑆 → {(∪ 𝑆 ∖ 𝐵), 𝐴} ≠ ∅)
25	12, 24	syl 17	. . 3 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → {(∪ 𝑆 ∖ 𝐵), 𝐴} ≠ ∅)
26		sigaclci 29522	. . 3 ⊢ (((𝑆 ∈ ∪ ran sigAlgebra ∧ {(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ 𝒫 𝑆) ∧ ({(∪ 𝑆 ∖ 𝐵), 𝐴} ≼ ω ∧ {(∪ 𝑆 ∖ 𝐵), 𝐴} ≠ ∅)) → ∩ {(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ 𝑆)
27	16, 21, 23, 25, 26	syl22anc 1319	. 2 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → ∩ {(∪ 𝑆 ∖ 𝐵), 𝐴} ∈ 𝑆)
28	15, 27	eqeltrd 2688	1 ⊢ ((𝑆 ∈ ∪ ran sigAlgebra ∧ 𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) → (𝐴 ∖ 𝐵) ∈ 𝑆)

Syntax hints:   → wi 4   ∧ w3a 1031   = wceq 1475   ∈ wcel 1977   ≠ wne 2780  ∀wral 2896   ∖ cdif 3537   ∩ cin 3539   ⊆ wss 3540  ∅c0 3874  𝒫 cpw 4108  {cpr 4127  ∪ cuni 4372  ∩ cint 4410   class class class wbr 4583  ran crn 5039  ωcom 6957   ≼ cdom 7839  sigAlgebracsiga 29497

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-8 1979  ax-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-rep 4699  ax-sep 4709  ax-nul 4717  ax-pow 4769  ax-pr 4833  ax-un 6847  ax-inf2 8421  ax-ac2 9168

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3or 1032  df-3an 1033  df-tru 1478  df-fal 1481  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-reu 2903  df-rmo 2904  df-rab 2905  df-v 3175  df-sbc 3403  df-csb 3500  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-pss 3556  df-nul 3875  df-if 4037  df-pw 4110  df-sn 4126  df-pr 4128  df-tp 4130  df-op 4132  df-uni 4373  df-int 4411  df-iun 4457  df-iin 4458  df-br 4584  df-opab 4644  df-mpt 4645  df-tr 4681  df-eprel 4949  df-id 4953  df-po 4959  df-so 4960  df-fr 4997  df-se 4998  df-we 4999  df-xp 5044  df-rel 5045  df-cnv 5046  df-co 5047  df-dm 5048  df-rn 5049  df-res 5050  df-ima 5051  df-pred 5597  df-ord 5643  df-on 5644  df-lim 5645  df-suc 5646  df-iota 5768  df-fun 5806  df-fn 5807  df-f 5808  df-f1 5809  df-fo 5810  df-f1o 5811  df-fv 5812  df-isom 5813  df-riota 6511  df-ov 6552  df-oprab 6553  df-mpt2 6554  df-om 6958  df-1st 7059  df-2nd 7060  df-wrecs 7294  df-recs 7355  df-rdg 7393  df-1o 7447  df-2o 7448  df-oadd 7451  df-er 7629  df-map 7746  df-en 7842  df-dom 7843  df-sdom 7844  df-fin 7845  df-oi 8298  df-card 8648  df-acn 8651  df-ac 8822  df-cda 8873  df-siga 29498

This theorem is referenced by:  inelsiga  29525  sigainb  29526  sigaldsys  29549  cldssbrsiga  29577  measxun2  29600  measssd  29605  measunl  29606  measiuns  29607  measiun  29608  meascnbl  29609  imambfm  29651  dya2iocbrsiga  29664  dya2icobrsiga  29665  sxbrsigalem2  29675  probdif  29809