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Mirrors > Home > MPE Home > Th. List > mbfres2 | Structured version Visualization version GIF version |
Description: Measurability of a piecewise function: if 𝐹 is measurable on subsets 𝐵 and 𝐶 of its domain, and these pieces make up all of 𝐴, then 𝐹 is measurable on the whole domain. (Contributed by Mario Carneiro, 18-Jun-2014.) |
Ref | Expression |
---|---|
mbfres2.1 | ⊢ (𝜑 → 𝐹:𝐴⟶ℝ) |
mbfres2.2 | ⊢ (𝜑 → (𝐹 ↾ 𝐵) ∈ MblFn) |
mbfres2.3 | ⊢ (𝜑 → (𝐹 ↾ 𝐶) ∈ MblFn) |
mbfres2.4 | ⊢ (𝜑 → (𝐵 ∪ 𝐶) = 𝐴) |
Ref | Expression |
---|---|
mbfres2 | ⊢ (𝜑 → 𝐹 ∈ MblFn) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mbfres2.4 | . . . . . . . . . . . 12 ⊢ (𝜑 → (𝐵 ∪ 𝐶) = 𝐴) | |
2 | 1 | reseq2d 5848 | . . . . . . . . . . 11 ⊢ (𝜑 → (𝐹 ↾ (𝐵 ∪ 𝐶)) = (𝐹 ↾ 𝐴)) |
3 | mbfres2.1 | . . . . . . . . . . . 12 ⊢ (𝜑 → 𝐹:𝐴⟶ℝ) | |
4 | ffn 6509 | . . . . . . . . . . . 12 ⊢ (𝐹:𝐴⟶ℝ → 𝐹 Fn 𝐴) | |
5 | fnresdm 6461 | . . . . . . . . . . . 12 ⊢ (𝐹 Fn 𝐴 → (𝐹 ↾ 𝐴) = 𝐹) | |
6 | 3, 4, 5 | 3syl 18 | . . . . . . . . . . 11 ⊢ (𝜑 → (𝐹 ↾ 𝐴) = 𝐹) |
7 | 2, 6 | eqtr2d 2857 | . . . . . . . . . 10 ⊢ (𝜑 → 𝐹 = (𝐹 ↾ (𝐵 ∪ 𝐶))) |
8 | 7 | adantr 483 | . . . . . . . . 9 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → 𝐹 = (𝐹 ↾ (𝐵 ∪ 𝐶))) |
9 | resundi 5862 | . . . . . . . . 9 ⊢ (𝐹 ↾ (𝐵 ∪ 𝐶)) = ((𝐹 ↾ 𝐵) ∪ (𝐹 ↾ 𝐶)) | |
10 | 8, 9 | syl6eq 2872 | . . . . . . . 8 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → 𝐹 = ((𝐹 ↾ 𝐵) ∪ (𝐹 ↾ 𝐶))) |
11 | 10 | cnveqd 5741 | . . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → ◡𝐹 = ◡((𝐹 ↾ 𝐵) ∪ (𝐹 ↾ 𝐶))) |
12 | cnvun 5996 | . . . . . . 7 ⊢ ◡((𝐹 ↾ 𝐵) ∪ (𝐹 ↾ 𝐶)) = (◡(𝐹 ↾ 𝐵) ∪ ◡(𝐹 ↾ 𝐶)) | |
13 | 11, 12 | syl6eq 2872 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → ◡𝐹 = (◡(𝐹 ↾ 𝐵) ∪ ◡(𝐹 ↾ 𝐶))) |
14 | 13 | imaeq1d 5923 | . . . . 5 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → (◡𝐹 “ 𝑥) = ((◡(𝐹 ↾ 𝐵) ∪ ◡(𝐹 ↾ 𝐶)) “ 𝑥)) |
15 | imaundir 6004 | . . . . 5 ⊢ ((◡(𝐹 ↾ 𝐵) ∪ ◡(𝐹 ↾ 𝐶)) “ 𝑥) = ((◡(𝐹 ↾ 𝐵) “ 𝑥) ∪ (◡(𝐹 ↾ 𝐶) “ 𝑥)) | |
16 | 14, 15 | syl6eq 2872 | . . . 4 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → (◡𝐹 “ 𝑥) = ((◡(𝐹 ↾ 𝐵) “ 𝑥) ∪ (◡(𝐹 ↾ 𝐶) “ 𝑥))) |
17 | mbfres2.2 | . . . . . . 7 ⊢ (𝜑 → (𝐹 ↾ 𝐵) ∈ MblFn) | |
18 | ssun1 4148 | . . . . . . . . . 10 ⊢ 𝐵 ⊆ (𝐵 ∪ 𝐶) | |
19 | 18, 1 | sseqtrid 4019 | . . . . . . . . 9 ⊢ (𝜑 → 𝐵 ⊆ 𝐴) |
20 | 3, 19 | fssresd 6540 | . . . . . . . 8 ⊢ (𝜑 → (𝐹 ↾ 𝐵):𝐵⟶ℝ) |
21 | ismbf 24223 | . . . . . . . 8 ⊢ ((𝐹 ↾ 𝐵):𝐵⟶ℝ → ((𝐹 ↾ 𝐵) ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐵) “ 𝑥) ∈ dom vol)) | |
22 | 20, 21 | syl 17 | . . . . . . 7 ⊢ (𝜑 → ((𝐹 ↾ 𝐵) ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐵) “ 𝑥) ∈ dom vol)) |
23 | 17, 22 | mpbid 234 | . . . . . 6 ⊢ (𝜑 → ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐵) “ 𝑥) ∈ dom vol) |
24 | 23 | r19.21bi 3208 | . . . . 5 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → (◡(𝐹 ↾ 𝐵) “ 𝑥) ∈ dom vol) |
25 | mbfres2.3 | . . . . . . 7 ⊢ (𝜑 → (𝐹 ↾ 𝐶) ∈ MblFn) | |
26 | ssun2 4149 | . . . . . . . . . 10 ⊢ 𝐶 ⊆ (𝐵 ∪ 𝐶) | |
27 | 26, 1 | sseqtrid 4019 | . . . . . . . . 9 ⊢ (𝜑 → 𝐶 ⊆ 𝐴) |
28 | 3, 27 | fssresd 6540 | . . . . . . . 8 ⊢ (𝜑 → (𝐹 ↾ 𝐶):𝐶⟶ℝ) |
29 | ismbf 24223 | . . . . . . . 8 ⊢ ((𝐹 ↾ 𝐶):𝐶⟶ℝ → ((𝐹 ↾ 𝐶) ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐶) “ 𝑥) ∈ dom vol)) | |
30 | 28, 29 | syl 17 | . . . . . . 7 ⊢ (𝜑 → ((𝐹 ↾ 𝐶) ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐶) “ 𝑥) ∈ dom vol)) |
31 | 25, 30 | mpbid 234 | . . . . . 6 ⊢ (𝜑 → ∀𝑥 ∈ ran (,)(◡(𝐹 ↾ 𝐶) “ 𝑥) ∈ dom vol) |
32 | 31 | r19.21bi 3208 | . . . . 5 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → (◡(𝐹 ↾ 𝐶) “ 𝑥) ∈ dom vol) |
33 | unmbl 24132 | . . . . 5 ⊢ (((◡(𝐹 ↾ 𝐵) “ 𝑥) ∈ dom vol ∧ (◡(𝐹 ↾ 𝐶) “ 𝑥) ∈ dom vol) → ((◡(𝐹 ↾ 𝐵) “ 𝑥) ∪ (◡(𝐹 ↾ 𝐶) “ 𝑥)) ∈ dom vol) | |
34 | 24, 32, 33 | syl2anc 586 | . . . 4 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → ((◡(𝐹 ↾ 𝐵) “ 𝑥) ∪ (◡(𝐹 ↾ 𝐶) “ 𝑥)) ∈ dom vol) |
35 | 16, 34 | eqeltrd 2913 | . . 3 ⊢ ((𝜑 ∧ 𝑥 ∈ ran (,)) → (◡𝐹 “ 𝑥) ∈ dom vol) |
36 | 35 | ralrimiva 3182 | . 2 ⊢ (𝜑 → ∀𝑥 ∈ ran (,)(◡𝐹 “ 𝑥) ∈ dom vol) |
37 | ismbf 24223 | . . 3 ⊢ (𝐹:𝐴⟶ℝ → (𝐹 ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡𝐹 “ 𝑥) ∈ dom vol)) | |
38 | 3, 37 | syl 17 | . 2 ⊢ (𝜑 → (𝐹 ∈ MblFn ↔ ∀𝑥 ∈ ran (,)(◡𝐹 “ 𝑥) ∈ dom vol)) |
39 | 36, 38 | mpbird 259 | 1 ⊢ (𝜑 → 𝐹 ∈ MblFn) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1533 ∈ wcel 2110 ∀wral 3138 ∪ cun 3934 ◡ccnv 5549 dom cdm 5550 ran crn 5551 ↾ cres 5552 “ cima 5553 Fn wfn 6345 ⟶wf 6346 ℝcr 10530 (,)cioo 12732 volcvol 24058 MblFncmbf 24209 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2156 ax-12 2172 ax-ext 2793 ax-rep 5183 ax-sep 5196 ax-nul 5203 ax-pow 5259 ax-pr 5322 ax-un 7455 ax-inf2 9098 ax-cnex 10587 ax-resscn 10588 ax-1cn 10589 ax-icn 10590 ax-addcl 10591 ax-addrcl 10592 ax-mulcl 10593 ax-mulrcl 10594 ax-mulcom 10595 ax-addass 10596 ax-mulass 10597 ax-distr 10598 ax-i2m1 10599 ax-1ne0 10600 ax-1rid 10601 ax-rnegex 10602 ax-rrecex 10603 ax-cnre 10604 ax-pre-lttri 10605 ax-pre-lttrn 10606 ax-pre-ltadd 10607 ax-pre-mulgt0 10608 ax-pre-sup 10609 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1536 df-fal 1546 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-nel 3124 df-ral 3143 df-rex 3144 df-reu 3145 df-rmo 3146 df-rab 3147 df-v 3497 df-sbc 3773 df-csb 3884 df-dif 3939 df-un 3941 df-in 3943 df-ss 3952 df-pss 3954 df-nul 4292 df-if 4468 df-pw 4541 df-sn 4562 df-pr 4564 df-tp 4566 df-op 4568 df-uni 4833 df-int 4870 df-iun 4914 df-br 5060 df-opab 5122 df-mpt 5140 df-tr 5166 df-id 5455 df-eprel 5460 df-po 5469 df-so 5470 df-fr 5509 df-se 5510 df-we 5511 df-xp 5556 df-rel 5557 df-cnv 5558 df-co 5559 df-dm 5560 df-rn 5561 df-res 5562 df-ima 5563 df-pred 6143 df-ord 6189 df-on 6190 df-lim 6191 df-suc 6192 df-iota 6309 df-fun 6352 df-fn 6353 df-f 6354 df-f1 6355 df-fo 6356 df-f1o 6357 df-fv 6358 df-isom 6359 df-riota 7108 df-ov 7153 df-oprab 7154 df-mpo 7155 df-of 7403 df-om 7575 df-1st 7683 df-2nd 7684 df-wrecs 7941 df-recs 8002 df-rdg 8040 df-1o 8096 df-2o 8097 df-oadd 8100 df-er 8283 df-map 8402 df-pm 8403 df-en 8504 df-dom 8505 df-sdom 8506 df-fin 8507 df-sup 8900 df-inf 8901 df-oi 8968 df-dju 9324 df-card 9362 df-pnf 10671 df-mnf 10672 df-xr 10673 df-ltxr 10674 df-le 10675 df-sub 10866 df-neg 10867 df-div 11292 df-nn 11633 df-2 11694 df-3 11695 df-n0 11892 df-z 11976 df-uz 12238 df-q 12343 df-rp 12384 df-xadd 12502 df-ioo 12736 df-ico 12738 df-icc 12739 df-fz 12887 df-fzo 13028 df-fl 13156 df-seq 13364 df-exp 13424 df-hash 13685 df-cj 14452 df-re 14453 df-im 14454 df-sqrt 14588 df-abs 14589 df-clim 14839 df-sum 15037 df-xmet 20532 df-met 20533 df-ovol 24059 df-vol 24060 df-mbf 24214 |
This theorem is referenced by: mbfss 24241 mbfresfi 34932 mbfposadd 34933 mbfres2cn 42235 |
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