Theorem issmfgelem 43790

Description: The predicate "𝐹 is a real-valued measurable function w.r.t. to the sigma-algebra 𝑆". A function is measurable iff the preimages of all left-closed intervals unbounded above are in the subspace sigma-algebra induced by its domain. The domain of 𝐹 is required to be a subset of the underlying set of 𝑆. Definition 121C of [Fremlin1] p. 36, and Proposition 121B (iv) of [Fremlin1] p. 36 . (Contributed by Glauco Siliprandi, 26-Jun-2021.)

Hypotheses

Ref	Expression
issmfgelem.x	⊢ Ⅎ𝑥𝜑
issmfgelem.a	⊢ Ⅎ𝑎𝜑
issmfgelem.s	⊢ (𝜑 → 𝑆 ∈ SAlg)
issmfgelem.d	⊢ 𝐷 = dom 𝐹
issmfgelem.i	⊢ (𝜑 → 𝐷 ⊆ ∪ 𝑆)
issmfgelem.f	⊢ (𝜑 → 𝐹:𝐷⟶ℝ)
issmfgelem.p	⊢ (𝜑 → ∀𝑎 ∈ ℝ {𝑥 ∈ 𝐷 ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))

Assertion

Ref	Expression
issmfgelem	⊢ (𝜑 → 𝐹 ∈ (SMblFn‘𝑆))

Distinct variable groups:   𝐷,𝑎,𝑥   𝐹,𝑎,𝑥   𝑆,𝑎,𝑥

Allowed substitution hints:   𝜑(𝑥,𝑎)

Proof of Theorem issmfgelem

Dummy variable 𝑏 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		issmfgelem.i	. . 3 ⊢ (𝜑 → 𝐷 ⊆ ∪ 𝑆)
2		issmfgelem.f	. . 3 ⊢ (𝜑 → 𝐹:𝐷⟶ℝ)
3		issmfgelem.s	. . . . . . . . 9 ⊢ (𝜑 → 𝑆 ∈ SAlg)
4	3, 1	restuni4 42151	. . . . . . . 8 ⊢ (𝜑 → ∪ (𝑆 ↾t 𝐷) = 𝐷)
5	4	eqcomd 2764	. . . . . . 7 ⊢ (𝜑 → 𝐷 = ∪ (𝑆 ↾t 𝐷))
6	5	rabeqdv 3397	. . . . . 6 ⊢ (𝜑 → {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} = {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ (𝐹‘𝑥) < 𝑏})
7	6	adantr 484	. . . . 5 ⊢ ((𝜑 ∧ 𝑏 ∈ ℝ) → {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} = {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ (𝐹‘𝑥) < 𝑏})
8		issmfgelem.x	. . . . . . 7 ⊢ Ⅎ𝑥𝜑
9		nfv 1915	. . . . . . 7 ⊢ Ⅎ𝑥 𝑏 ∈ ℝ
10	8, 9	nfan 1900	. . . . . 6 ⊢ Ⅎ𝑥(𝜑 ∧ 𝑏 ∈ ℝ)
11		issmfgelem.a	. . . . . . 7 ⊢ Ⅎ𝑎𝜑
12		nfv 1915	. . . . . . 7 ⊢ Ⅎ𝑎 𝑏 ∈ ℝ
13	11, 12	nfan 1900	. . . . . 6 ⊢ Ⅎ𝑎(𝜑 ∧ 𝑏 ∈ ℝ)
14	3	uniexd 7466	. . . . . . . . . . 11 ⊢ (𝜑 → ∪ 𝑆 ∈ V)
15	14	adantr 484	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝐷 ⊆ ∪ 𝑆) → ∪ 𝑆 ∈ V)
16		simpr 488	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝐷 ⊆ ∪ 𝑆) → 𝐷 ⊆ ∪ 𝑆)
17	15, 16	ssexd 5194	. . . . . . . . 9 ⊢ ((𝜑 ∧ 𝐷 ⊆ ∪ 𝑆) → 𝐷 ∈ V)
18	1, 17	mpdan 686	. . . . . . . 8 ⊢ (𝜑 → 𝐷 ∈ V)
19		eqid 2758	. . . . . . . 8 ⊢ (𝑆 ↾t 𝐷) = (𝑆 ↾t 𝐷)
20	3, 18, 19	subsalsal 43387	. . . . . . 7 ⊢ (𝜑 → (𝑆 ↾t 𝐷) ∈ SAlg)
21	20	adantr 484	. . . . . 6 ⊢ ((𝜑 ∧ 𝑏 ∈ ℝ) → (𝑆 ↾t 𝐷) ∈ SAlg)
22		eqid 2758	. . . . . 6 ⊢ ∪ (𝑆 ↾t 𝐷) = ∪ (𝑆 ↾t 𝐷)
23	2	adantr 484	. . . . . . . . 9 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → 𝐹:𝐷⟶ℝ)
24		simpr 488	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → 𝑥 ∈ ∪ (𝑆 ↾t 𝐷))
25	4	adantr 484	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → ∪ (𝑆 ↾t 𝐷) = 𝐷)
26	24, 25	eleqtrd 2854	. . . . . . . . 9 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → 𝑥 ∈ 𝐷)
27	23, 26	ffvelrnd 6843	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → (𝐹‘𝑥) ∈ ℝ)
28	27	rexrd 10729	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → (𝐹‘𝑥) ∈ ℝ*)
29	28	adantlr 714	. . . . . 6 ⊢ (((𝜑 ∧ 𝑏 ∈ ℝ) ∧ 𝑥 ∈ ∪ (𝑆 ↾t 𝐷)) → (𝐹‘𝑥) ∈ ℝ*)
30		issmfgelem.p	. . . . . . . . . 10 ⊢ (𝜑 → ∀𝑎 ∈ ℝ {𝑥 ∈ 𝐷 ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
31	5	rabeqdv 3397	. . . . . . . . . . . 12 ⊢ (𝜑 → {𝑥 ∈ 𝐷 ∣ 𝑎 ≤ (𝐹‘𝑥)} = {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)})
32	31	eleq1d 2836	. . . . . . . . . . 11 ⊢ (𝜑 → ({𝑥 ∈ 𝐷 ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷) ↔ {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷)))
33	11, 32	ralbid 3159	. . . . . . . . . 10 ⊢ (𝜑 → (∀𝑎 ∈ ℝ {𝑥 ∈ 𝐷 ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷) ↔ ∀𝑎 ∈ ℝ {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷)))
34	30, 33	mpbid 235	. . . . . . . . 9 ⊢ (𝜑 → ∀𝑎 ∈ ℝ {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
35	34	adantr 484	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑎 ∈ ℝ) → ∀𝑎 ∈ ℝ {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
36		simpr 488	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑎 ∈ ℝ) → 𝑎 ∈ ℝ)
37		rspa 3135	. . . . . . . 8 ⊢ ((∀𝑎 ∈ ℝ {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷) ∧ 𝑎 ∈ ℝ) → {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
38	35, 36, 37	syl2anc 587	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑎 ∈ ℝ) → {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
39	38	adantlr 714	. . . . . 6 ⊢ (((𝜑 ∧ 𝑏 ∈ ℝ) ∧ 𝑎 ∈ ℝ) → {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ 𝑎 ≤ (𝐹‘𝑥)} ∈ (𝑆 ↾t 𝐷))
40		simpr 488	. . . . . 6 ⊢ ((𝜑 ∧ 𝑏 ∈ ℝ) → 𝑏 ∈ ℝ)
41	10, 13, 21, 22, 29, 39, 40	salpreimagelt 43731	. . . . 5 ⊢ ((𝜑 ∧ 𝑏 ∈ ℝ) → {𝑥 ∈ ∪ (𝑆 ↾t 𝐷) ∣ (𝐹‘𝑥) < 𝑏} ∈ (𝑆 ↾t 𝐷))
42	7, 41	eqeltrd 2852	. . . 4 ⊢ ((𝜑 ∧ 𝑏 ∈ ℝ) → {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} ∈ (𝑆 ↾t 𝐷))
43	42	ralrimiva 3113	. . 3 ⊢ (𝜑 → ∀𝑏 ∈ ℝ {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} ∈ (𝑆 ↾t 𝐷))
44	1, 2, 43	3jca 1125	. 2 ⊢ (𝜑 → (𝐷 ⊆ ∪ 𝑆 ∧ 𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} ∈ (𝑆 ↾t 𝐷)))
45		issmfgelem.d	. . 3 ⊢ 𝐷 = dom 𝐹
46	3, 45	issmf 43750	. 2 ⊢ (𝜑 → (𝐹 ∈ (SMblFn‘𝑆) ↔ (𝐷 ⊆ ∪ 𝑆 ∧ 𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑥 ∈ 𝐷 ∣ (𝐹‘𝑥) < 𝑏} ∈ (𝑆 ↾t 𝐷))))
47	44, 46	mpbird 260	1 ⊢ (𝜑 → 𝐹 ∈ (SMblFn‘𝑆))

Syntax hints:   → wi 4   ∧ wa 399   ∧ w3a 1084   = wceq 1538  Ⅎwnf 1785   ∈ wcel 2111  ∀wral 3070  {crab 3074  Vcvv 3409   ⊆ wss 3858  ∪ cuni 4798   class class class wbr 5032  dom cdm 5524  ⟶wf 6331  ‘cfv 6335  (class class class)co 7150  ℝcr 10574  ℝ^*cxr 10712   < clt 10713   ≤ cle 10714   ↾_t crest 16752  SAlgcsalg 43338  SMblFncsmblfn 43722

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 2729  ax-rep 5156  ax-sep 5169  ax-nul 5176  ax-pow 5234  ax-pr 5298  ax-un 7459  ax-inf2 9137  ax-cc 9895  ax-ac2 9923  ax-cnex 10631  ax-resscn 10632  ax-1cn 10633  ax-icn 10634  ax-addcl 10635  ax-addrcl 10636  ax-mulcl 10637  ax-mulrcl 10638  ax-mulcom 10639  ax-addass 10640  ax-mulass 10641  ax-distr 10642  ax-i2m1 10643  ax-1ne0 10644  ax-1rid 10645  ax-rnegex 10646  ax-rrecex 10647  ax-cnre 10648  ax-pre-lttri 10649  ax-pre-lttrn 10650  ax-pre-ltadd 10651  ax-pre-mulgt0 10652

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3or 1085  df-3an 1086  df-tru 1541  df-fal 1551  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2557  df-eu 2588  df-clab 2736  df-cleq 2750  df-clel 2830  df-nfc 2901  df-ne 2952  df-nel 3056  df-ral 3075  df-rex 3076  df-reu 3077  df-rmo 3078  df-rab 3079  df-v 3411  df-sbc 3697  df-csb 3806  df-dif 3861  df-un 3863  df-in 3865  df-ss 3875  df-pss 3877  df-nul 4226  df-if 4421  df-pw 4496  df-sn 4523  df-pr 4525  df-tp 4527  df-op 4529  df-uni 4799  df-int 4839  df-iun 4885  df-br 5033  df-opab 5095  df-mpt 5113  df-tr 5139  df-id 5430  df-eprel 5435  df-po 5443  df-so 5444  df-fr 5483  df-se 5484  df-we 5485  df-xp 5530  df-rel 5531  df-cnv 5532  df-co 5533  df-dm 5534  df-rn 5535  df-res 5536  df-ima 5537  df-pred 6126  df-ord 6172  df-on 6173  df-lim 6174  df-suc 6175  df-iota 6294  df-fun 6337  df-fn 6338  df-f 6339  df-f1 6340  df-fo 6341  df-f1o 6342  df-fv 6343  df-isom 6344  df-riota 7108  df-ov 7153  df-oprab 7154  df-mpo 7155  df-om 7580  df-1st 7693  df-2nd 7694  df-wrecs 7957  df-recs 8018  df-rdg 8056  df-1o 8112  df-er 8299  df-map 8418  df-pm 8419  df-en 8528  df-dom 8529  df-sdom 8530  df-fin 8531  df-card 9401  df-acn 9404  df-ac 9576  df-pnf 10715  df-mnf 10716  df-xr 10717  df-ltxr 10718  df-le 10719  df-sub 10910  df-neg 10911  df-nn 11675  df-n0 11935  df-z 12021  df-uz 12283  df-ioo 12783  df-ico 12785  df-rest 16754  df-salg 43339  df-smblfn 43723

This theorem is referenced by:  issmfge  43791