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Theorem issmfle 41275
 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 right closed intervals unbounded below are in the subspace sigma-algebra induced by its domain. The domain of 𝐹 is required to be b subset of the underlying set of 𝑆. Definition 121C of [Fremlin1] p. 36, and Proposition 121B (ii) of [Fremlin1] p. 35 . (Contributed by Glauco Siliprandi, 26-Jun-2021.)
Hypotheses
Ref Expression
issmfle.s (𝜑𝑆 ∈ SAlg)
issmfle.d 𝐷 = dom 𝐹
Assertion
Ref Expression
issmfle (𝜑 → (𝐹 ∈ (SMblFn‘𝑆) ↔ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑎 ∈ ℝ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷))))
Distinct variable groups:   𝐷,𝑎,𝑥   𝐹,𝑎,𝑥   𝑆,𝑎
Allowed substitution hints:   𝜑(𝑥,𝑎)   𝑆(𝑥)

Proof of Theorem issmfle
Dummy variables 𝑏 𝑦 𝑐 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 issmfle.s . . . . . . 7 (𝜑𝑆 ∈ SAlg)
21adantr 480 . . . . . 6 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝑆 ∈ SAlg)
3 simpr 476 . . . . . 6 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝐹 ∈ (SMblFn‘𝑆))
4 issmfle.d . . . . . 6 𝐷 = dom 𝐹
52, 3, 4smfdmss 41263 . . . . 5 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝐷 𝑆)
62, 3, 4smff 41262 . . . . 5 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝐹:𝐷⟶ℝ)
7 nfv 1883 . . . . . . 7 𝑏𝜑
8 nfv 1883 . . . . . . 7 𝑏 𝐹 ∈ (SMblFn‘𝑆)
97, 8nfan 1868 . . . . . 6 𝑏(𝜑𝐹 ∈ (SMblFn‘𝑆))
10 nfv 1883 . . . . . . . . . 10 𝑦𝜑
11 nfv 1883 . . . . . . . . . 10 𝑦 𝐹 ∈ (SMblFn‘𝑆)
1210, 11nfan 1868 . . . . . . . . 9 𝑦(𝜑𝐹 ∈ (SMblFn‘𝑆))
13 nfv 1883 . . . . . . . . 9 𝑦 𝑏 ∈ ℝ
1412, 13nfan 1868 . . . . . . . 8 𝑦((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ)
15 nfv 1883 . . . . . . . 8 𝑐((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ)
161uniexd 39595 . . . . . . . . . . . . 13 (𝜑 𝑆 ∈ V)
1716adantr 480 . . . . . . . . . . . 12 ((𝜑𝐷 𝑆) → 𝑆 ∈ V)
18 simpr 476 . . . . . . . . . . . 12 ((𝜑𝐷 𝑆) → 𝐷 𝑆)
1917, 18ssexd 4838 . . . . . . . . . . 11 ((𝜑𝐷 𝑆) → 𝐷 ∈ V)
205, 19syldan 486 . . . . . . . . . 10 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝐷 ∈ V)
21 eqid 2651 . . . . . . . . . 10 (𝑆t 𝐷) = (𝑆t 𝐷)
222, 20, 21subsalsal 40895 . . . . . . . . 9 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → (𝑆t 𝐷) ∈ SAlg)
2322adantr 480 . . . . . . . 8 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) → (𝑆t 𝐷) ∈ SAlg)
246frexr 39917 . . . . . . . . . 10 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → 𝐹:𝐷⟶ℝ*)
2524adantr 480 . . . . . . . . 9 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) → 𝐹:𝐷⟶ℝ*)
2625ffvelrnda 6399 . . . . . . . 8 ((((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) ∧ 𝑦𝐷) → (𝐹𝑦) ∈ ℝ*)
272adantr 480 . . . . . . . . . 10 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑐 ∈ ℝ) → 𝑆 ∈ SAlg)
283adantr 480 . . . . . . . . . 10 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑐 ∈ ℝ) → 𝐹 ∈ (SMblFn‘𝑆))
29 simpr 476 . . . . . . . . . 10 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑐 ∈ ℝ) → 𝑐 ∈ ℝ)
3027, 28, 4, 29smfpreimalt 41261 . . . . . . . . 9 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑐 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) < 𝑐} ∈ (𝑆t 𝐷))
3130adantlr 751 . . . . . . . 8 ((((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) ∧ 𝑐 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) < 𝑐} ∈ (𝑆t 𝐷))
32 simpr 476 . . . . . . . 8 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) → 𝑏 ∈ ℝ)
3314, 15, 23, 26, 31, 32salpreimaltle 41256 . . . . . . 7 (((𝜑𝐹 ∈ (SMblFn‘𝑆)) ∧ 𝑏 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
3433ex 449 . . . . . 6 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → (𝑏 ∈ ℝ → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)))
359, 34ralrimi 2986 . . . . 5 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
365, 6, 353jca 1261 . . . 4 ((𝜑𝐹 ∈ (SMblFn‘𝑆)) → (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)))
3736ex 449 . . 3 (𝜑 → (𝐹 ∈ (SMblFn‘𝑆) → (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))))
38 nfv 1883 . . . . . . 7 𝑦 𝐷 𝑆
39 nfv 1883 . . . . . . 7 𝑦 𝐹:𝐷⟶ℝ
40 nfcv 2793 . . . . . . . 8 𝑦
41 nfrab1 3152 . . . . . . . . 9 𝑦{𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏}
42 nfcv 2793 . . . . . . . . 9 𝑦(𝑆t 𝐷)
4341, 42nfel 2806 . . . . . . . 8 𝑦{𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)
4440, 43nfral 2974 . . . . . . 7 𝑦𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)
4538, 39, 44nf3an 1871 . . . . . 6 𝑦(𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
4610, 45nfan 1868 . . . . 5 𝑦(𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)))
47 nfv 1883 . . . . . . 7 𝑏 𝐷 𝑆
48 nfv 1883 . . . . . . 7 𝑏 𝐹:𝐷⟶ℝ
49 nfra1 2970 . . . . . . 7 𝑏𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)
5047, 48, 49nf3an 1871 . . . . . 6 𝑏(𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
517, 50nfan 1868 . . . . 5 𝑏(𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)))
521adantr 480 . . . . 5 ((𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))) → 𝑆 ∈ SAlg)
53 simpr1 1087 . . . . 5 ((𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))) → 𝐷 𝑆)
54 simpr2 1088 . . . . 5 ((𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))) → 𝐹:𝐷⟶ℝ)
55 rspa 2959 . . . . . . 7 ((∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷) ∧ 𝑏 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
56553ad2antl3 1245 . . . . . 6 (((𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)) ∧ 𝑏 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
5756adantll 750 . . . . 5 (((𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))) ∧ 𝑏 ∈ ℝ) → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))
5846, 51, 52, 4, 53, 54, 57issmflelem 41274 . . . 4 ((𝜑 ∧ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))) → 𝐹 ∈ (SMblFn‘𝑆))
5958ex 449 . . 3 (𝜑 → ((𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)) → 𝐹 ∈ (SMblFn‘𝑆)))
6037, 59impbid 202 . 2 (𝜑 → (𝐹 ∈ (SMblFn‘𝑆) ↔ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷))))
61 breq2 4689 . . . . . . . 8 (𝑏 = 𝑎 → ((𝐹𝑦) ≤ 𝑏 ↔ (𝐹𝑦) ≤ 𝑎))
6261rabbidv 3220 . . . . . . 7 (𝑏 = 𝑎 → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} = {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑎})
63 fveq2 6229 . . . . . . . . . 10 (𝑦 = 𝑥 → (𝐹𝑦) = (𝐹𝑥))
6463breq1d 4695 . . . . . . . . 9 (𝑦 = 𝑥 → ((𝐹𝑦) ≤ 𝑎 ↔ (𝐹𝑥) ≤ 𝑎))
6564cbvrabv 3230 . . . . . . . 8 {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑎} = {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎}
6665a1i 11 . . . . . . 7 (𝑏 = 𝑎 → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑎} = {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎})
6762, 66eqtrd 2685 . . . . . 6 (𝑏 = 𝑎 → {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} = {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎})
6867eleq1d 2715 . . . . 5 (𝑏 = 𝑎 → ({𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷) ↔ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷)))
6968cbvralv 3201 . . . 4 (∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷) ↔ ∀𝑎 ∈ ℝ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷))
70693anbi3i 1274 . . 3 ((𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)) ↔ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑎 ∈ ℝ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷)))
7170a1i 11 . 2 (𝜑 → ((𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑏 ∈ ℝ {𝑦𝐷 ∣ (𝐹𝑦) ≤ 𝑏} ∈ (𝑆t 𝐷)) ↔ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑎 ∈ ℝ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷))))
7260, 71bitrd 268 1 (𝜑 → (𝐹 ∈ (SMblFn‘𝑆) ↔ (𝐷 𝑆𝐹:𝐷⟶ℝ ∧ ∀𝑎 ∈ ℝ {𝑥𝐷 ∣ (𝐹𝑥) ≤ 𝑎} ∈ (𝑆t 𝐷))))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 196   ∧ wa 383   ∧ w3a 1054   = wceq 1523   ∈ wcel 2030  ∀wral 2941  {crab 2945  Vcvv 3231   ⊆ wss 3607  ∪ cuni 4468   class class class wbr 4685  dom cdm 5143  ⟶wf 5922  ‘cfv 5926  (class class class)co 6690  ℝcr 9973  ℝ*cxr 10111   < clt 10112   ≤ cle 10113   ↾t crest 16128  SAlgcsalg 40846  SMblFncsmblfn 41230 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-8 2032  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631  ax-rep 4804  ax-sep 4814  ax-nul 4822  ax-pow 4873  ax-pr 4936  ax-un 6991  ax-inf2 8576  ax-cc 9295  ax-ac2 9323  ax-cnex 10030  ax-resscn 10031  ax-1cn 10032  ax-icn 10033  ax-addcl 10034  ax-addrcl 10035  ax-mulcl 10036  ax-mulrcl 10037  ax-mulcom 10038  ax-addass 10039  ax-mulass 10040  ax-distr 10041  ax-i2m1 10042  ax-1ne0 10043  ax-1rid 10044  ax-rnegex 10045  ax-rrecex 10046  ax-cnre 10047  ax-pre-lttri 10048  ax-pre-lttrn 10049  ax-pre-ltadd 10050  ax-pre-mulgt0 10051  ax-pre-sup 10052 This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3or 1055  df-3an 1056  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-eu 2502  df-mo 2503  df-clab 2638  df-cleq 2644  df-clel 2647  df-nfc 2782  df-ne 2824  df-nel 2927  df-ral 2946  df-rex 2947  df-reu 2948  df-rmo 2949  df-rab 2950  df-v 3233  df-sbc 3469  df-csb 3567  df-dif 3610  df-un 3612  df-in 3614  df-ss 3621  df-pss 3623  df-nul 3949  df-if 4120  df-pw 4193  df-sn 4211  df-pr 4213  df-tp 4215  df-op 4217  df-uni 4469  df-int 4508  df-iun 4554  df-iin 4555  df-br 4686  df-opab 4746  df-mpt 4763  df-tr 4786  df-id 5053  df-eprel 5058  df-po 5064  df-so 5065  df-fr 5102  df-se 5103  df-we 5104  df-xp 5149  df-rel 5150  df-cnv 5151  df-co 5152  df-dm 5153  df-rn 5154  df-res 5155  df-ima 5156  df-pred 5718  df-ord 5764  df-on 5765  df-lim 5766  df-suc 5767  df-iota 5889  df-fun 5928  df-fn 5929  df-f 5930  df-f1 5931  df-fo 5932  df-f1o 5933  df-fv 5934  df-isom 5935  df-riota 6651  df-ov 6693  df-oprab 6694  df-mpt2 6695  df-om 7108  df-1st 7210  df-2nd 7211  df-wrecs 7452  df-recs 7513  df-rdg 7551  df-1o 7605  df-oadd 7609  df-er 7787  df-map 7901  df-pm 7902  df-en 7998  df-dom 7999  df-sdom 8000  df-fin 8001  df-sup 8389  df-inf 8390  df-card 8803  df-acn 8806  df-ac 8977  df-pnf 10114  df-mnf 10115  df-xr 10116  df-ltxr 10117  df-le 10118  df-sub 10306  df-neg 10307  df-div 10723  df-nn 11059  df-n0 11331  df-z 11416  df-uz 11726  df-q 11827  df-rp 11871  df-ioo 12217  df-ico 12219  df-fl 12633  df-rest 16130  df-salg 40847  df-smblfn 41231 This theorem is referenced by:  smfpreimale  41284  issmfgt  41286  issmfled  41287
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