Theorem meaiunincf 46870

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 1916	. . . . . 6 ⊢ Ⅎ𝑛 𝑘 ∈ 𝑍
7	5, 6	nfan 1901	. . . . 5 ⊢ Ⅎ𝑛(𝜑 ∧ 𝑘 ∈ 𝑍)
8		meaiunincf.f	. . . . . . 7 ⊢ Ⅎ𝑛𝐸
9		nfcv 2899	. . . . . . 7 ⊢ Ⅎ𝑛𝑘
10	8, 9	nffv 6854	. . . . . 6 ⊢ Ⅎ𝑛(𝐸‘𝑘)
11		nfcv 2899	. . . . . . 7 ⊢ Ⅎ𝑛(𝑘 + 1)
12	8, 11	nffv 6854	. . . . . 6 ⊢ Ⅎ𝑛(𝐸‘(𝑘 + 1))
13	10, 12	nfss 3928	. . . . 5 ⊢ Ⅎ𝑛(𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1))
14	7, 13	nfim 1898	. . . 4 ⊢ Ⅎ𝑛((𝜑 ∧ 𝑘 ∈ 𝑍) → (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1)))
15		eleq1w 2820	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝑛 ∈ 𝑍 ↔ 𝑘 ∈ 𝑍))
16	15	anbi2d 631	. . . . 5 ⊢ (𝑛 = 𝑘 → ((𝜑 ∧ 𝑛 ∈ 𝑍) ↔ (𝜑 ∧ 𝑘 ∈ 𝑍)))
17		fveq2 6844	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝐸‘𝑛) = (𝐸‘𝑘))
18		fvoveq1 7393	. . . . . 6 ⊢ (𝑛 = 𝑘 → (𝐸‘(𝑛 + 1)) = (𝐸‘(𝑘 + 1)))
19	17, 18	sseq12d 3969	. . . . 5 ⊢ (𝑛 = 𝑘 → ((𝐸‘𝑛) ⊆ (𝐸‘(𝑛 + 1)) ↔ (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1))))
20	16, 19	imbi12d 344	. . . 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 2248	. . 3 ⊢ ((𝜑 ∧ 𝑘 ∈ 𝑍) → (𝐸‘𝑘) ⊆ (𝐸‘(𝑘 + 1)))
23		meaiunincf.x	. . . 4 ⊢ (𝜑 → ∃𝑥 ∈ ℝ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥)
24		breq2 5104	. . . . . . 7 ⊢ (𝑥 = 𝑦 → ((𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ (𝑀‘(𝐸‘𝑛)) ≤ 𝑦))
25	24	ralbidv 3161	. . . . . 6 ⊢ (𝑥 = 𝑦 → (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑦))
26		nfv 1916	. . . . . . . 8 ⊢ Ⅎ𝑘(𝑀‘(𝐸‘𝑛)) ≤ 𝑦
27		nfcv 2899	. . . . . . . . . 10 ⊢ Ⅎ𝑛𝑀
28	27, 10	nffv 6854	. . . . . . . . 9 ⊢ Ⅎ𝑛(𝑀‘(𝐸‘𝑘))
29		nfcv 2899	. . . . . . . . 9 ⊢ Ⅎ𝑛 ≤
30		nfcv 2899	. . . . . . . . 9 ⊢ Ⅎ𝑛𝑦
31	28, 29, 30	nfbr 5147	. . . . . . . 8 ⊢ Ⅎ𝑛(𝑀‘(𝐸‘𝑘)) ≤ 𝑦
32		2fveq3 6849	. . . . . . . . 9 ⊢ (𝑛 = 𝑘 → (𝑀‘(𝐸‘𝑛)) = (𝑀‘(𝐸‘𝑘)))
33	32	breq1d 5110	. . . . . . . 8 ⊢ (𝑛 = 𝑘 → ((𝑀‘(𝐸‘𝑛)) ≤ 𝑦 ↔ (𝑀‘(𝐸‘𝑘)) ≤ 𝑦))
34	26, 31, 33	cbvralw 3280	. . . . . . 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 279	. . . . 5 ⊢ (𝑥 = 𝑦 → (∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦))
37	36	cbvrexvw 3217	. . . 4 ⊢ (∃𝑥 ∈ ℝ ∀𝑛 ∈ 𝑍 (𝑀‘(𝐸‘𝑛)) ≤ 𝑥 ↔ ∃𝑦 ∈ ℝ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦)
38	23, 37	sylib 218	. . 3 ⊢ (𝜑 → ∃𝑦 ∈ ℝ ∀𝑘 ∈ 𝑍 (𝑀‘(𝐸‘𝑘)) ≤ 𝑦)
39		meaiunincf.s	. . . 4 ⊢ 𝑆 = (𝑛 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑛)))
40		nfcv 2899	. . . . 5 ⊢ Ⅎ𝑘(𝑀‘(𝐸‘𝑛))
41	40, 28, 32	cbvmpt 5202	. . . 4 ⊢ (𝑛 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑛))) = (𝑘 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑘)))
42	39, 41	eqtri 2760	. . 3 ⊢ 𝑆 = (𝑘 ∈ 𝑍 ↦ (𝑀‘(𝐸‘𝑘)))
43	1, 2, 3, 4, 22, 38, 42	meaiuninc 46868	. 2 ⊢ (𝜑 → 𝑆 ⇝ (𝑀‘∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘)))
44		nfcv 2899	. . . 4 ⊢ Ⅎ𝑘(𝐸‘𝑛)
45		fveq2 6844	. . . 4 ⊢ (𝑘 = 𝑛 → (𝐸‘𝑘) = (𝐸‘𝑛))
46	10, 44, 45	cbviun 4992	. . 3 ⊢ ∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘) = ∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛)
47	46	fveq2i 6847	. 2 ⊢ (𝑀‘∪ 𝑘 ∈ 𝑍 (𝐸‘𝑘)) = (𝑀‘∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛))
48	43, 47	breqtrdi 5141	1 ⊢ (𝜑 → 𝑆 ⇝ (𝑀‘∪ 𝑛 ∈ 𝑍 (𝐸‘𝑛)))

Syntax hints:   → wi 4   ↔ wb 206   ∧ wa 395   = wceq 1542  Ⅎwnf 1785   ∈ wcel 2114  Ⅎwnfc 2884  ∀wral 3052  ∃wrex 3062   ⊆ wss 3903  ∪ ciun 4948   class class class wbr 5100   ↦ cmpt 5181  dom cdm 5634  ⟶wf 6498  ‘cfv 6502  (class class class)co 7370  ℝcr 11039  1c1 11041   + caddc 11043   ≤ cle 11181  ℤcz 12502  ℤ_≥cuz 12765   ⇝ cli 15421  Meascmea 46836

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 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-10 2147  ax-11 2163  ax-12 2185  ax-ext 2709  ax-rep 5226  ax-sep 5245  ax-nul 5255  ax-pow 5314  ax-pr 5381  ax-un 7692  ax-inf2 9564  ax-cnex 11096  ax-resscn 11097  ax-1cn 11098  ax-icn 11099  ax-addcl 11100  ax-addrcl 11101  ax-mulcl 11102  ax-mulrcl 11103  ax-mulcom 11104  ax-addass 11105  ax-mulass 11106  ax-distr 11107  ax-i2m1 11108  ax-1ne0 11109  ax-1rid 11110  ax-rnegex 11111  ax-rrecex 11112  ax-cnre 11113  ax-pre-lttri 11114  ax-pre-lttrn 11115  ax-pre-ltadd 11116  ax-pre-mulgt0 11117  ax-pre-sup 11118

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-3or 1088  df-3an 1089  df-tru 1545  df-fal 1555  df-ex 1782  df-nf 1786  df-sb 2069  df-mo 2540  df-eu 2570  df-clab 2716  df-cleq 2729  df-clel 2812  df-nfc 2886  df-ne 2934  df-nel 3038  df-ral 3053  df-rex 3063  df-rmo 3352  df-reu 3353  df-rab 3402  df-v 3444  df-sbc 3743  df-csb 3852  df-dif 3906  df-un 3908  df-in 3910  df-ss 3920  df-pss 3923  df-nul 4288  df-if 4482  df-pw 4558  df-sn 4583  df-pr 4585  df-op 4589  df-uni 4866  df-int 4905  df-iun 4950  df-disj 5068  df-br 5101  df-opab 5163  df-mpt 5182  df-tr 5208  df-id 5529  df-eprel 5534  df-po 5542  df-so 5543  df-fr 5587  df-se 5588  df-we 5589  df-xp 5640  df-rel 5641  df-cnv 5642  df-co 5643  df-dm 5644  df-rn 5645  df-res 5646  df-ima 5647  df-pred 6269  df-ord 6330  df-on 6331  df-lim 6332  df-suc 6333  df-iota 6458  df-fun 6504  df-fn 6505  df-f 6506  df-f1 6507  df-fo 6508  df-f1o 6509  df-fv 6510  df-isom 6511  df-riota 7327  df-ov 7373  df-oprab 7374  df-mpo 7375  df-om 7821  df-1st 7945  df-2nd 7946  df-frecs 8235  df-wrecs 8266  df-recs 8315  df-rdg 8353  df-1o 8409  df-2o 8410  df-oadd 8413  df-omul 8414  df-er 8647  df-map 8779  df-en 8898  df-dom 8899  df-sdom 8900  df-fin 8901  df-sup 9359  df-oi 9429  df-card 9865  df-acn 9868  df-pnf 11182  df-mnf 11183  df-xr 11184  df-ltxr 11185  df-le 11186  df-sub 11380  df-neg 11381  df-div 11809  df-nn 12160  df-2 12222  df-3 12223  df-n0 12416  df-z 12503  df-uz 12766  df-rp 12920  df-xadd 13041  df-ico 13281  df-icc 13282  df-fz 13438  df-fzo 13585  df-seq 13939  df-exp 13999  df-hash 14268  df-cj 15036  df-re 15037  df-im 15038  df-sqrt 15172  df-abs 15173  df-clim 15425  df-sum 15624  df-salg 46696  df-sumge0 46750  df-mea 46837

This theorem is referenced by:  meaiuninc3v  46871