icombl - Metamath Proof Explorer

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Theorem icombl 23848

Description: A closed-below, open-above real interval is measurable. (Contributed by Mario Carneiro, 16-Jun-2014.)

**Assertion**
Ref	Expression
icombl	⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → (𝐴[,)𝐵) ∈ dom vol)

**Proof of Theorem icombl**
Step	Hyp	Ref	Expression
1		uncom 4052	. . . . 5 ⊢ ((𝐵[,)+∞) ∪ (𝐴[,)𝐵)) = ((𝐴[,)𝐵) ∪ (𝐵[,)+∞))
2		rexr 10536	. . . . . . 7 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℝ^*)
3	2	ad2antrr 722	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^) ∧ 𝐴 < 𝐵) → 𝐴 ∈ ℝ^)
4		simplr 765	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^) ∧ 𝐴 < 𝐵) → 𝐵 ∈ ℝ^)
5		pnfxr 10544	. . . . . . 7 ⊢ +∞ ∈ ℝ^*
6	5	a1i 11	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^) ∧ 𝐴 < 𝐵) → +∞ ∈ ℝ^)
7		xrltle 12392	. . . . . . . 8 ⊢ ((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^*) → (𝐴 < 𝐵 → 𝐴 ≤ 𝐵))
8	2, 7	sylan 580	. . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → (𝐴 < 𝐵 → 𝐴 ≤ 𝐵))
9	8	imp 407	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → 𝐴 ≤ 𝐵)
10		pnfge 12375	. . . . . . 7 ⊢ (𝐵 ∈ ℝ^* → 𝐵 ≤ +∞)
11	4, 10	syl 17	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → 𝐵 ≤ +∞)
12		icoun 12711	. . . . . 6 ⊢ (((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) ∧ (𝐴 ≤ 𝐵 ∧ 𝐵 ≤ +∞)) → ((𝐴[,)𝐵) ∪ (𝐵[,)+∞)) = (𝐴[,)+∞))
13	3, 4, 6, 9, 11, 12	syl32anc 1371	. . . . 5 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐴[,)𝐵) ∪ (𝐵[,)+∞)) = (𝐴[,)+∞))
14	1, 13	syl5eq 2842	. . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐵[,)+∞) ∪ (𝐴[,)𝐵)) = (𝐴[,)+∞))
15		ssun1 4071	. . . . . 6 ⊢ (𝐵[,)+∞) ⊆ ((𝐵[,)+∞) ∪ (𝐴[,)𝐵))
16	15, 14	sseqtrid 3942	. . . . 5 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵[,)+∞) ⊆ (𝐴[,)+∞))
17		incom 4101	. . . . . 6 ⊢ ((𝐵[,)+∞) ∩ (𝐴[,)𝐵)) = ((𝐴[,)𝐵) ∩ (𝐵[,)+∞))
18		icodisj 12712	. . . . . . . 8 ⊢ ((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) → ((𝐴[,)𝐵) ∩ (𝐵[,)+∞)) = ∅)
19	5, 18	mp3an3 1442	. . . . . . 7 ⊢ ((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^*) → ((𝐴[,)𝐵) ∩ (𝐵[,)+∞)) = ∅)
20	3, 4, 19	syl2anc 584	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐴[,)𝐵) ∩ (𝐵[,)+∞)) = ∅)
21	17, 20	syl5eq 2842	. . . . 5 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐵[,)+∞) ∩ (𝐴[,)𝐵)) = ∅)
22		uneqdifeq 4354	. . . . 5 ⊢ (((𝐵[,)+∞) ⊆ (𝐴[,)+∞) ∧ ((𝐵[,)+∞) ∩ (𝐴[,)𝐵)) = ∅) → (((𝐵[,)+∞) ∪ (𝐴[,)𝐵)) = (𝐴[,)+∞) ↔ ((𝐴[,)+∞) ∖ (𝐵[,)+∞)) = (𝐴[,)𝐵)))
23	16, 21, 22	syl2anc 584	. . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (((𝐵[,)+∞) ∪ (𝐴[,)𝐵)) = (𝐴[,)+∞) ↔ ((𝐴[,)+∞) ∖ (𝐵[,)+∞)) = (𝐴[,)𝐵)))
24	14, 23	mpbid 233	. . 3 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐴[,)+∞) ∖ (𝐵[,)+∞)) = (𝐴[,)𝐵))
25		icombl1 23847	. . . . 5 ⊢ (𝐴 ∈ ℝ → (𝐴[,)+∞) ∈ dom vol)
26	25	ad2antrr 722	. . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐴[,)+∞) ∈ dom vol)
27		xrleloe 12387	. . . . . . . 8 ⊢ ((𝐵 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) → (𝐵 ≤ +∞ ↔ (𝐵 < +∞ ∨ 𝐵 = +∞)))
28	4, 6, 27	syl2anc 584	. . . . . . 7 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵 ≤ +∞ ↔ (𝐵 < +∞ ∨ 𝐵 = +∞)))
29	11, 28	mpbid 233	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵 < +∞ ∨ 𝐵 = +∞))
30		simpr 485	. . . . . . . 8 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → 𝐴 < 𝐵)
31		xrre2 12413	. . . . . . . . 9 ⊢ (((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) ∧ (𝐴 < 𝐵 ∧ 𝐵 < +∞)) → 𝐵 ∈ ℝ)
32	31	expr 457	. . . . . . . 8 ⊢ (((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^* ∧ +∞ ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵 < +∞ → 𝐵 ∈ ℝ))
33	3, 4, 6, 30, 32	syl31anc 1366	. . . . . . 7 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵 < +∞ → 𝐵 ∈ ℝ))
34	33	orim1d 960	. . . . . 6 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐵 < +∞ ∨ 𝐵 = +∞) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞)))
35	29, 34	mpd 15	. . . . 5 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞))
36		icombl1 23847	. . . . . 6 ⊢ (𝐵 ∈ ℝ → (𝐵[,)+∞) ∈ dom vol)
37		oveq1 7026	. . . . . . . 8 ⊢ (𝐵 = +∞ → (𝐵[,)+∞) = (+∞[,)+∞))
38		pnfge 12375	. . . . . . . . . 10 ⊢ (+∞ ∈ ℝ^* → +∞ ≤ +∞)
39	5, 38	ax-mp 5	. . . . . . . . 9 ⊢ +∞ ≤ +∞
40		ico0 12634	. . . . . . . . . 10 ⊢ ((+∞ ∈ ℝ^* ∧ +∞ ∈ ℝ^*) → ((+∞[,)+∞) = ∅ ↔ +∞ ≤ +∞))
41	5, 5, 40	mp2an 688	. . . . . . . . 9 ⊢ ((+∞[,)+∞) = ∅ ↔ +∞ ≤ +∞)
42	39, 41	mpbir 232	. . . . . . . 8 ⊢ (+∞[,)+∞) = ∅
43	37, 42	syl6eq 2846	. . . . . . 7 ⊢ (𝐵 = +∞ → (𝐵[,)+∞) = ∅)
44		0mbl 23823	. . . . . . 7 ⊢ ∅ ∈ dom vol
45	43, 44	syl6eqel 2890	. . . . . 6 ⊢ (𝐵 = +∞ → (𝐵[,)+∞) ∈ dom vol)
46	36, 45	jaoi 852	. . . . 5 ⊢ ((𝐵 ∈ ℝ ∨ 𝐵 = +∞) → (𝐵[,)+∞) ∈ dom vol)
47	35, 46	syl 17	. . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐵[,)+∞) ∈ dom vol)
48		difmbl 23827	. . . 4 ⊢ (((𝐴[,)+∞) ∈ dom vol ∧ (𝐵[,)+∞) ∈ dom vol) → ((𝐴[,)+∞) ∖ (𝐵[,)+∞)) ∈ dom vol)
49	26, 47, 48	syl2anc 584	. . 3 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → ((𝐴[,)+∞) ∖ (𝐵[,)+∞)) ∈ dom vol)
50	24, 49	eqeltrrd 2883	. 2 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ 𝐴 < 𝐵) → (𝐴[,)𝐵) ∈ dom vol)
51		ico0 12634	. . . . . 6 ⊢ ((𝐴 ∈ ℝ^* ∧ 𝐵 ∈ ℝ^*) → ((𝐴[,)𝐵) = ∅ ↔ 𝐵 ≤ 𝐴))
52	2, 51	sylan 580	. . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → ((𝐴[,)𝐵) = ∅ ↔ 𝐵 ≤ 𝐴))
53		simpr 485	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^) → 𝐵 ∈ ℝ^)
54	2	adantr 481	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^) → 𝐴 ∈ ℝ^)
55	53, 54	xrlenltd 10556	. . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → (𝐵 ≤ 𝐴 ↔ ¬ 𝐴 < 𝐵))
56	52, 55	bitrd 280	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → ((𝐴[,)𝐵) = ∅ ↔ ¬ 𝐴 < 𝐵))
57	56	biimpar 478	. . 3 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ ¬ 𝐴 < 𝐵) → (𝐴[,)𝐵) = ∅)
58	57, 44	syl6eqel 2890	. 2 ⊢ (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) ∧ ¬ 𝐴 < 𝐵) → (𝐴[,)𝐵) ∈ dom vol)
59	50, 58	pm2.61dan 809	1 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ^*) → (𝐴[,)𝐵) ∈ dom vol)

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 207 ∧ wa 396 ∨ wo 842 ∧ w3a 1080 = wceq 1522 ∈ wcel 2080 ∖ cdif 3858 ∪ cun 3859 ∩ cin 3860 ⊆ wss 3861 ∅c0 4213 class class class wbr 4964 dom cdm 5446 (class class class)co 7019 ℝcr 10385 +∞cpnf 10521 ℝ^*cxr 10523 < clt 10524 ≤ cle 10525 [,)cico 12590 volcvol 23747

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1778 ax-4 1792 ax-5 1889 ax-6 1948 ax-7 1993 ax-8 2082 ax-9 2090 ax-10 2111 ax-11 2125 ax-12 2140 ax-13 2343 ax-ext 2768 ax-rep 5084 ax-sep 5097 ax-nul 5104 ax-pow 5160 ax-pr 5224 ax-un 7322 ax-inf2 8953 ax-cnex 10442 ax-resscn 10443 ax-1cn 10444 ax-icn 10445 ax-addcl 10446 ax-addrcl 10447 ax-mulcl 10448 ax-mulrcl 10449 ax-mulcom 10450 ax-addass 10451 ax-mulass 10452 ax-distr 10453 ax-i2m1 10454 ax-1ne0 10455 ax-1rid 10456 ax-rnegex 10457 ax-rrecex 10458 ax-cnre 10459 ax-pre-lttri 10460 ax-pre-lttrn 10461 ax-pre-ltadd 10462 ax-pre-mulgt0 10463 ax-pre-sup 10464

This theorem depends on definitions: df-bi 208 df-an 397 df-or 843 df-3or 1081 df-3an 1082 df-tru 1525 df-fal 1535 df-ex 1763 df-nf 1767 df-sb 2042 df-mo 2575 df-eu 2611 df-clab 2775 df-cleq 2787 df-clel 2862 df-nfc 2934 df-ne 2984 df-nel 3090 df-ral 3109 df-rex 3110 df-reu 3111 df-rmo 3112 df-rab 3113 df-v 3438 df-sbc 3708 df-csb 3814 df-dif 3864 df-un 3866 df-in 3868 df-ss 3876 df-pss 3878 df-nul 4214 df-if 4384 df-pw 4457 df-sn 4475 df-pr 4477 df-tp 4479 df-op 4481 df-uni 4748 df-int 4785 df-iun 4829 df-br 4965 df-opab 5027 df-mpt 5044 df-tr 5067 df-id 5351 df-eprel 5356 df-po 5365 df-so 5366 df-fr 5405 df-se 5406 df-we 5407 df-xp 5452 df-rel 5453 df-cnv 5454 df-co 5455 df-dm 5456 df-rn 5457 df-res 5458 df-ima 5459 df-pred 6026 df-ord 6072 df-on 6073 df-lim 6074 df-suc 6075 df-iota 6192 df-fun 6230 df-fn 6231 df-f 6232 df-f1 6233 df-fo 6234 df-f1o 6235 df-fv 6236 df-isom 6237 df-riota 6980 df-ov 7022 df-oprab 7023 df-mpo 7024 df-of 7270 df-om 7440 df-1st 7548 df-2nd 7549 df-wrecs 7801 df-recs 7863 df-rdg 7901 df-1o 7956 df-2o 7957 df-oadd 7960 df-er 8142 df-map 8261 df-pm 8262 df-en 8361 df-dom 8362 df-sdom 8363 df-fin 8364 df-sup 8755 df-inf 8756 df-oi 8823 df-dju 9179 df-card 9217 df-pnf 10526 df-mnf 10527 df-xr 10528 df-ltxr 10529 df-le 10530 df-sub 10721 df-neg 10722 df-div 11148 df-nn 11489 df-2 11550 df-3 11551 df-n0 11748 df-z 11832 df-uz 12094 df-q 12198 df-rp 12240 df-xadd 12358 df-ioo 12592 df-ico 12594 df-icc 12595 df-fz 12743 df-fzo 12884 df-fl 13012 df-seq 13220 df-exp 13280 df-hash 13541 df-cj 14292 df-re 14293 df-im 14294 df-sqrt 14428 df-abs 14429 df-clim 14679 df-rlim 14680 df-sum 14877 df-xmet 20220 df-met 20221 df-ovol 23748 df-vol 23749

This theorem is referenced by: ioombl 23849 volicoff 41836 voliooicof 41837 icoresmbl 42381 hoiprodcl 42385 hoiprodcl3 42418 hoidmvcl 42420 hsphoidmvle2 42423 hsphoidmvle 42424 hoidmv1lelem1 42429 hoidmv1lelem2 42430 hoidmv1lelem3 42431 hoidifhspdmvle 42458 volicorege0 42475 ovolval5lem1 42490

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