Theorem meaiunincf 47409

Description: Measures are continuous from below (bounded case): if 𝐸 is a sequence of nondecreasing measurable sets (with bounded measure) then the measure of the union is the limit of the measures. This is Proposition 112C (e) of [Fremlin1] p. 16. (Contributed by Glauco Siliprandi, 13-Feb-2022.)

Hypotheses

Ref	Expression
meaiunincf.p	⊢ Ⅎ𝑛𝜑
meaiunincf.f	⊢ Ⅎ𝑛𝐸
meaiunincf.m	⊢ (𝜑 → 𝑀 ∈ Meas)
meaiunincf.n	⊢ (𝜑 → 𝑁 ∈ ℤ)
meaiunincf.z	⊢ 𝑍 = (ℤ≥‘𝑁)
meaiunincf.e	⊢ (𝜑 → 𝐸:𝑍⟶dom 𝑀)
meaiunincf.i	⊢ ((𝜑 ∧ 𝑛 ∈ 𝑍) → (𝐸‘𝑛) ⊆ (𝐸‘(𝑛 + 1)))
meaiunincf.x	⊢ (𝜑 → ∃𝑥 ∈ ℝ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥)
meaiunincf.s	⊢ 𝑆 = (𝑛 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑛)))

Assertion

Ref	Expression
meaiunincf	⊢ (𝜑 → 𝑆 ⇝ (𝑀‘∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛)))

Distinct variable groups:   𝑥,𝐸   𝑛,𝑀,𝑥   𝑛,𝑍,𝑥

Allowed substitution hints:   𝜑(𝑥, 𝑛)   𝑆(𝑥, 𝑛)   𝐸(𝑛)   𝑁(𝑥, 𝑛)

Proof of Theorem meaiunincf

Dummy variables 𝑘 𝑦 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		meaiunincf.m	. . 3 ⊢ (𝜑 → 𝑀 ∈ Meas)
2		meaiunincf.n	. . 3 ⊢ (𝜑 → 𝑁 ∈ ℤ)
3		meaiunincf.z	. . 3 ⊢ 𝑍 = (ℤ≥‘𝑁)
4		meaiunincf.e	. . 3 ⊢ (𝜑 → 𝐸:𝑍⟶dom 𝑀)
5		meaiunincf.p	. . . . . 6 ⊢ Ⅎ𝑛𝜑
6		nfv 1947	. . . . . 6 ⊢ Ⅎ𝑛 𝑘 ∈ 𝑍
7	5, 6	nfan 1932	. . . . 5 ⊢ Ⅎ𝑛(𝜑 ∧ 𝑘 ∈ 𝑍)
8		meaiunincf.f	. . . . . . 7 ⊢ Ⅎ𝑛𝐸
9		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑛𝑘
10	8, 9	nffv 6884	. . . . . 6 ⊢ Ⅎ𝑛(𝐸‘𝑘)
11		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑛(𝑘 + 1)
12	8, 11	nffv 6884	. . . . . 6 ⊢ Ⅎ𝑛(𝐸‘(𝑘 + 1))
13	10, 12	nfss 3924	. . . . 5 ⊢ Ⅎ𝑛(𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1))
14	7, 13	nfim 1929	. . . 4 ⊢ Ⅎ𝑛((𝜑 ∧ 𝑘 ∈ 𝑍) → (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1)))
15		eleq1w 2843	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝑛 ∈ 𝑍 ↔ 𝑘 ∈ 𝑍))
16	15	anbi2d 642	. . . . 5 ⊢ (𝑛 = 𝑘 → ((𝜑 ∧ 𝑛 ∈ 𝑍) ↔ (𝜑 ∧ 𝑘 ∈ 𝑍)))
17		fveq2 6874	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝐸‘𝑛) = (𝐸‘𝑘))
18		fvoveq1 7432	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝐸‘(𝑛 + 1)) = (𝐸‘(𝑘 + 1)))
19	17, 18	sseq12d 3964	. . . . 5 ⊢ (𝑛 = 𝑘 → ((𝐸‘𝑛) ⊆ (𝐸‘(𝑛 + 1)) ↔ (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1))))
20	16, 19	imbi12d 347	. . . 4 ⊢ (𝑛 = 𝑘 → (((𝜑 ∧ 𝑛 ∈ 𝑍) → (𝐸‘𝑛) ⊆ (𝐸‘(𝑛 + 1))) ↔ ((𝜑 ∧ 𝑘 ∈ 𝑍) → (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1)))))
21		meaiunincf.i	. . . 4 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑍) → (𝐸‘𝑛) ⊆ (𝐸‘(𝑛 + 1)))
22	14, 20, 21	chvarfv 2276	. . 3 ⊢ ((𝜑 ∧ 𝑘 ∈ 𝑍) → (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1)))
23		meaiunincf.x	. . . 4 ⊢ (𝜑 → ∃𝑥 ∈ ℝ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥)
24		breq2 5107	. . . . . . 7 ⊢ (𝑥 = 𝑦 → ((𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ (𝑀‘(𝐸‘𝑛)) ≤ 𝑦))
25	24	ralbidv 3185	. . . . . 6 ⊢ (𝑥 = 𝑦 → (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑦))
26		nfv 1947	. . . . . . . 8 ⊢ Ⅎ𝑘(𝑀‘(𝐸‘𝑛)) ≤ 𝑦
27		nfcv 2922	. . . . . . . . . 10 ⊢ Ⅎ𝑛𝑀
28	27, 10	nffv 6884	. . . . . . . . 9 ⊢ Ⅎ𝑛(𝑀‘(𝐸‘𝑘))
29		nfcv 2922	. . . . . . . . 9 ⊢ Ⅎ𝑛 ≤
30		nfcv 2922	. . . . . . . . 9 ⊢ Ⅎ𝑛𝑦
31	28, 29, 30	nfbr 5152	. . . . . . . 8 ⊢ Ⅎ𝑛(𝑀‘(𝐸‘𝑘)) ≤ 𝑦
32		2fveq3 6879	. . . . . . . . 9 ⊢ (𝑛 = 𝑘 → (𝑀‘(𝐸‘𝑛)) = (𝑀‘(𝐸‘𝑘)))
33	32	breq1d 5113	. . . . . . . 8 ⊢ (𝑛 = 𝑘 → ((𝑀‘(𝐸‘𝑛)) ≤ 𝑦 ↔ (𝑀‘(𝐸‘𝑘)) ≤ 𝑦))
34	26, 31, 33	cbvralw 3304	. . . . . . 7 ⊢ (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑦 ↔ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦)
35	34	a1i 11	. . . . . 6 ⊢ (𝑥 = 𝑦 → (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑦 ↔ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦))
36	25, 35	bitrd 282	. . . . 5 ⊢ (𝑥 = 𝑦 → (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦))
37	36	cbvrexvw 3241	. . . 4 ⊢ (∃𝑥 ∈ ℝ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∃𝑦 ∈ ℝ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦)
38	23, 37	sylib 221	. . 3 ⊢ (𝜑 → ∃𝑦 ∈ ℝ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦)
39		meaiunincf.s	. . . 4 ⊢ 𝑆 = (𝑛 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑛)))
40		nfcv 2922	. . . . 5 ⊢ Ⅎ𝑘(𝑀‘(𝐸‘𝑛))
41	40, 28, 32	cbvmpt 5207	. . . 4 ⊢ (𝑛 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑛))) = (𝑘 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑘)))
42	39, 41	eqtri 2783	. . 3 ⊢ 𝑆 = (𝑘 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑘)))
43	1, 2, 3, 4, 22, 38, 42	meaiuninc 47407	. 2 ⊢ (𝜑 → 𝑆 ⇝ (𝑀‘∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘)))
44		nfcv 2922	. . . 4 ⊢ Ⅎ𝑘(𝐸‘𝑛)
45		fveq2 6874	. . . 4 ⊢ (𝑘 = 𝑛 → (𝐸‘𝑘) = (𝐸‘𝑛))
46	10, 44, 45	cbviun 4993	. . 3 ⊢ ∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘) = ∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛)
47	46	fveq2i 6877	. 2 ⊢ (𝑀‘∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘)) = (𝑀‘∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛))
48	43, 47	breqtrdi 5146	1 ⊢ (𝜑 → 𝑆 ⇝ (𝑀‘∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛)))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1570  Ⅎwnf 1816   ∈ wcel 2145  Ⅎwnfc 2907  ∀wral 3076  ∃wrex 3086   ⊆ wss 3899  ∪ ciun 4951   class class class wbr 5103   ↦ cmpt 5186  dom cdm 5648  ⟶wf 6524  ‘cfv 6528  (class class class)co 7409  ℝcr 11156  1c1 11158   + caddc 11160   ≤ cle 11301  ℤcz 12648  ℤ_≥cuz 12920   ⇝ cli 15604  Meascmea 47375

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2213  ax-ext 2732  ax-rep 5232  ax-sep 5249  ax-nul 5260  ax-pow 5327  ax-pr 5391  ax-un 7735  ax-inf2 9620  ax-cnex 11213  ax-resscn 11214  ax-1cn 11215  ax-icn 11216  ax-addcl 11217  ax-addrcl 11218  ax-mulcl 11219  ax-mulrcl 11220  ax-mulcom 11221  ax-addass 11222  ax-mulass 11223  ax-distr 11224  ax-i2m1 11225  ax-1ne0 11226  ax-1rid 11227  ax-rnegex 11228  ax-rrecex 11229  ax-cnre 11230  ax-pre-lttri 11231  ax-pre-lttrn 11232  ax-pre-ltadd 11233  ax-pre-mulgt0 11234  ax-pre-sup 11235

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-nel 3062  df-ral 3077  df-rex 3087  df-rmo 3365  df-reu 3366  df-rab 3413  df-v 3452  df-sbc 3740  df-csb 3848  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-pss 3919  df-nul 4280  df-if 4483  df-pw 4559  df-sn 4585  df-pr 4587  df-op 4591  df-uni 4868  df-int 4908  df-iun 4953  df-disj 5071  df-br 5104  df-opab 5168  df-mpt 5187  df-tr 5213  df-id 5543  df-eprel 5548  df-po 5556  df-so 5557  df-fr 5601  df-se 5602  df-we 5603  df-xp 5654  df-rel 5655  df-cnv 5656  df-co 5657  df-dm 5658  df-rn 5659  df-res 5660  df-ima 5661  df-pred 6294  df-ord 6355  df-on 6356  df-lim 6357  df-suc 6358  df-iota 6484  df-fun 6530  df-fn 6531  df-f 6532  df-f1 6533  df-fo 6534  df-f1o 6535  df-fv 6536  df-isom 6537  df-riota 7366  df-ov 7412  df-oprab 7413  df-mpo 7414  df-om 7862  df-1st 7985  df-2nd 7986  df-frecs 8278  df-wrecs 8309  df-recs 8358  df-rdg 8397  df-1o 8455  df-2o 8456  df-oadd 8459  df-omul 8460  df-er 8696  df-map 8828  df-en 8953  df-dom 8954  df-sdom 8955  df-fin 8956  df-sup 9412  df-oi 9482  df-card 9977  df-acn 9980  df-pnf 11302  df-mnf 11303  df-xr 11304  df-ltxr 11305  df-le 11306  df-sub 11500  df-neg 11501  df-div 11929  df-nn 12291  df-2 12360  df-3 12361  df-n0 12562  df-z 12649  df-uz 12921  df-rp 13076  df-xadd 13197  df-ico 13437  df-icc 13438  df-fz 13595  df-fzo 13743  df-seq 14099  df-exp 14159  df-hash 14428  df-cj 15219  df-re 15220  df-im 15221  df-sqrt 15355  df-abs 15356  df-clim 15608  df-sum 15807  df-salg 47235  df-sumge0 47289  df-mea 47376

This theorem is used by:  meaiuninc3v  47410