dvbdfbdioo - Mathbox for Glauco Siliprandi

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Theorem dvbdfbdioo 39451

Description: A function on an open interval, with bounded derivative, is bounded. (Contributed by Glauco Siliprandi, 11-Dec-2019.)

**Hypotheses**
Ref	Expression
dvbdfbdioo.a	⊢ (𝜑 → 𝐴 ∈ ℝ)
dvbdfbdioo.b	⊢ (𝜑 → 𝐵 ∈ ℝ)
dvbdfbdioo.altb	⊢ (𝜑 → 𝐴 < 𝐵)
dvbdfbdioo.f	⊢ (𝜑 → 𝐹:(𝐴(,)𝐵)⟶ℝ)
dvbdfbdioo.dmdv	⊢ (𝜑 → dom (ℝ D 𝐹) = (𝐴(,)𝐵))
dvbdfbdioo.dvbd	⊢ (𝜑 → ∃𝑎 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎)

**Assertion**
Ref	Expression
dvbdfbdioo	⊢ (𝜑 → ∃𝑏 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏)

Distinct variable groups: 𝐴,𝑎,𝑏,𝑥 𝐵,𝑎,𝑏,𝑥 𝐹,𝑎,𝑏,𝑥 𝜑,𝑎 Allowed substitution hints: 𝜑(𝑥,𝑏)

Proof of Theorem dvbdfbdioo Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		dvbdfbdioo.f	. . . . . . . 8 ⊢ (𝜑 → 𝐹:(𝐴(,)𝐵)⟶ℝ)
2		dvbdfbdioo.a	. . . . . . . . . 10 ⊢ (𝜑 → 𝐴 ∈ ℝ)
3	2	rexrd 10033	. . . . . . . . 9 ⊢ (𝜑 → 𝐴 ∈ ℝ^*)
4		dvbdfbdioo.b	. . . . . . . . . 10 ⊢ (𝜑 → 𝐵 ∈ ℝ)
5	4	rexrd 10033	. . . . . . . . 9 ⊢ (𝜑 → 𝐵 ∈ ℝ^*)
6	2, 4	readdcld 10013	. . . . . . . . . 10 ⊢ (𝜑 → (𝐴 + 𝐵) ∈ ℝ)
7	6	rehalfcld 11223	. . . . . . . . 9 ⊢ (𝜑 → ((𝐴 + 𝐵) / 2) ∈ ℝ)
8		dvbdfbdioo.altb	. . . . . . . . . 10 ⊢ (𝜑 → 𝐴 < 𝐵)
9		avglt1 11214	. . . . . . . . . . 11 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 < 𝐵 ↔ 𝐴 < ((𝐴 + 𝐵) / 2)))
10	2, 4, 9	syl2anc 692	. . . . . . . . . 10 ⊢ (𝜑 → (𝐴 < 𝐵 ↔ 𝐴 < ((𝐴 + 𝐵) / 2)))
11	8, 10	mpbid 222	. . . . . . . . 9 ⊢ (𝜑 → 𝐴 < ((𝐴 + 𝐵) / 2))
12		avglt2 11215	. . . . . . . . . . 11 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 < 𝐵 ↔ ((𝐴 + 𝐵) / 2) < 𝐵))
13	2, 4, 12	syl2anc 692	. . . . . . . . . 10 ⊢ (𝜑 → (𝐴 < 𝐵 ↔ ((𝐴 + 𝐵) / 2) < 𝐵))
14	8, 13	mpbid 222	. . . . . . . . 9 ⊢ (𝜑 → ((𝐴 + 𝐵) / 2) < 𝐵)
15	3, 5, 7, 11, 14	eliood 39131	. . . . . . . 8 ⊢ (𝜑 → ((𝐴 + 𝐵) / 2) ∈ (𝐴(,)𝐵))
16	1, 15	ffvelrnd 6316	. . . . . . 7 ⊢ (𝜑 → (𝐹‘((𝐴 + 𝐵) / 2)) ∈ ℝ)
17	16	recnd 10012	. . . . . 6 ⊢ (𝜑 → (𝐹‘((𝐴 + 𝐵) / 2)) ∈ ℂ)
18	17	abscld 14109	. . . . 5 ⊢ (𝜑 → (abs‘(𝐹‘((𝐴 + 𝐵) / 2))) ∈ ℝ)
19	18	ad2antrr 761	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → (abs‘(𝐹‘((𝐴 + 𝐵) / 2))) ∈ ℝ)
20		simplr 791	. . . . 5 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → 𝑎 ∈ ℝ)
21	4	ad2antrr 761	. . . . . 6 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → 𝐵 ∈ ℝ)
22	2	ad2antrr 761	. . . . . 6 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → 𝐴 ∈ ℝ)
23	21, 22	resubcld 10402	. . . . 5 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → (𝐵 − 𝐴) ∈ ℝ)
24	20, 23	remulcld 10014	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → (𝑎 · (𝐵 − 𝐴)) ∈ ℝ)
25	19, 24	readdcld 10013	. . 3 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) ∈ ℝ)
26	8	ad2antrr 761	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → 𝐴 < 𝐵)
27	1	ad2antrr 761	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → 𝐹:(𝐴(,)𝐵)⟶ℝ)
28		dvbdfbdioo.dmdv	. . . . 5 ⊢ (𝜑 → dom (ℝ D 𝐹) = (𝐴(,)𝐵))
29	28	ad2antrr 761	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → dom (ℝ D 𝐹) = (𝐴(,)𝐵))
30		fveq2 6148	. . . . . . . . 9 ⊢ (𝑥 = 𝑦 → ((ℝ D 𝐹)‘𝑥) = ((ℝ D 𝐹)‘𝑦))
31	30	fveq2d 6152	. . . . . . . 8 ⊢ (𝑥 = 𝑦 → (abs‘((ℝ D 𝐹)‘𝑥)) = (abs‘((ℝ D 𝐹)‘𝑦)))
32	31	breq1d 4623	. . . . . . 7 ⊢ (𝑥 = 𝑦 → ((abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎 ↔ (abs‘((ℝ D 𝐹)‘𝑦)) ≤ 𝑎))
33	32	cbvralv 3159	. . . . . 6 ⊢ (∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎 ↔ ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑦)) ≤ 𝑎)
34	33	biimpi 206	. . . . 5 ⊢ (∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎 → ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑦)) ≤ 𝑎)
35	34	adantl 482	. . . 4 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑦)) ≤ 𝑎)
36		eqid 2621	. . . 4 ⊢ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) = ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴)))
37	22, 21, 26, 27, 29, 20, 35, 36	dvbdfbdioolem2 39450	. . 3 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))))
38		fveq2 6148	. . . . . . . 8 ⊢ (𝑥 = 𝑦 → (𝐹‘𝑥) = (𝐹‘𝑦))
39	38	fveq2d 6152	. . . . . . 7 ⊢ (𝑥 = 𝑦 → (abs‘(𝐹‘𝑥)) = (abs‘(𝐹‘𝑦)))
40	39	breq1d 4623	. . . . . 6 ⊢ (𝑥 = 𝑦 → ((abs‘(𝐹‘𝑥)) ≤ 𝑏 ↔ (abs‘(𝐹‘𝑦)) ≤ 𝑏))
41	40	cbvralv 3159	. . . . 5 ⊢ (∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏 ↔ ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ 𝑏)
42		breq2 4617	. . . . . 6 ⊢ (𝑏 = ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) → ((abs‘(𝐹‘𝑦)) ≤ 𝑏 ↔ (abs‘(𝐹‘𝑦)) ≤ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴)))))
43	42	ralbidv 2980	. . . . 5 ⊢ (𝑏 = ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) → (∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ 𝑏 ↔ ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴)))))
44	41, 43	syl5bb 272	. . . 4 ⊢ (𝑏 = ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) → (∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏 ↔ ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴)))))
45	44	rspcev 3295	. . 3 ⊢ ((((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴))) ∈ ℝ ∧ ∀𝑦 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑦)) ≤ ((abs‘(𝐹‘((𝐴 + 𝐵) / 2))) + (𝑎 · (𝐵 − 𝐴)))) → ∃𝑏 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏)
46	25, 37, 45	syl2anc 692	. 2 ⊢ (((𝜑 ∧ 𝑎 ∈ ℝ) ∧ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎) → ∃𝑏 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏)
47		dvbdfbdioo.dvbd	. 2 ⊢ (𝜑 → ∃𝑎 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘((ℝ D 𝐹)‘𝑥)) ≤ 𝑎)
48	46, 47	r19.29a 3071	1 ⊢ (𝜑 → ∃𝑏 ∈ ℝ ∀𝑥 ∈ (𝐴(,)𝐵)(abs‘(𝐹‘𝑥)) ≤ 𝑏)

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 196 ∧ wa 384 = wceq 1480 ∈ wcel 1987 ∀wral 2907 ∃wrex 2908 class class class wbr 4613 dom cdm 5074 ⟶wf 5843 ‘cfv 5847 (class class class)co 6604 ℝcr 9879 + caddc 9883 · cmul 9885 < clt 10018 ≤ cle 10019 − cmin 10210 / cdiv 10628 2c2 11014 (,)cioo 12117 abscabs 13908 D cdv 23533

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1719 ax-4 1734 ax-5 1836 ax-6 1885 ax-7 1932 ax-8 1989 ax-9 1996 ax-10 2016 ax-11 2031 ax-12 2044 ax-13 2245 ax-ext 2601 ax-rep 4731 ax-sep 4741 ax-nul 4749 ax-pow 4803 ax-pr 4867 ax-un 6902 ax-inf2 8482 ax-cnex 9936 ax-resscn 9937 ax-1cn 9938 ax-icn 9939 ax-addcl 9940 ax-addrcl 9941 ax-mulcl 9942 ax-mulrcl 9943 ax-mulcom 9944 ax-addass 9945 ax-mulass 9946 ax-distr 9947 ax-i2m1 9948 ax-1ne0 9949 ax-1rid 9950 ax-rnegex 9951 ax-rrecex 9952 ax-cnre 9953 ax-pre-lttri 9954 ax-pre-lttrn 9955 ax-pre-ltadd 9956 ax-pre-mulgt0 9957 ax-pre-sup 9958 ax-addf 9959 ax-mulf 9960

This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1037 df-3an 1038 df-tru 1483 df-ex 1702 df-nf 1707 df-sb 1878 df-eu 2473 df-mo 2474 df-clab 2608 df-cleq 2614 df-clel 2617 df-nfc 2750 df-ne 2791 df-nel 2894 df-ral 2912 df-rex 2913 df-reu 2914 df-rmo 2915 df-rab 2916 df-v 3188 df-sbc 3418 df-csb 3515 df-dif 3558 df-un 3560 df-in 3562 df-ss 3569 df-pss 3571 df-nul 3892 df-if 4059 df-pw 4132 df-sn 4149 df-pr 4151 df-tp 4153 df-op 4155 df-uni 4403 df-int 4441 df-iun 4487 df-iin 4488 df-br 4614 df-opab 4674 df-mpt 4675 df-tr 4713 df-eprel 4985 df-id 4989 df-po 4995 df-so 4996 df-fr 5033 df-se 5034 df-we 5035 df-xp 5080 df-rel 5081 df-cnv 5082 df-co 5083 df-dm 5084 df-rn 5085 df-res 5086 df-ima 5087 df-pred 5639 df-ord 5685 df-on 5686 df-lim 5687 df-suc 5688 df-iota 5810 df-fun 5849 df-fn 5850 df-f 5851 df-f1 5852 df-fo 5853 df-f1o 5854 df-fv 5855 df-isom 5856 df-riota 6565 df-ov 6607 df-oprab 6608 df-mpt2 6609 df-of 6850 df-om 7013 df-1st 7113 df-2nd 7114 df-supp 7241 df-wrecs 7352 df-recs 7413 df-rdg 7451 df-1o 7505 df-2o 7506 df-oadd 7509 df-er 7687 df-map 7804 df-pm 7805 df-ixp 7853 df-en 7900 df-dom 7901 df-sdom 7902 df-fin 7903 df-fsupp 8220 df-fi 8261 df-sup 8292 df-inf 8293 df-oi 8359 df-card 8709 df-cda 8934 df-pnf 10020 df-mnf 10021 df-xr 10022 df-ltxr 10023 df-le 10024 df-sub 10212 df-neg 10213 df-div 10629 df-nn 10965 df-2 11023 df-3 11024 df-4 11025 df-5 11026 df-6 11027 df-7 11028 df-8 11029 df-9 11030 df-n0 11237 df-z 11322 df-dec 11438 df-uz 11632 df-q 11733 df-rp 11777 df-xneg 11890 df-xadd 11891 df-xmul 11892 df-ioo 12121 df-ico 12123 df-icc 12124 df-fz 12269 df-fzo 12407 df-seq 12742 df-exp 12801 df-hash 13058 df-cj 13773 df-re 13774 df-im 13775 df-sqrt 13909 df-abs 13910 df-struct 15783 df-ndx 15784 df-slot 15785 df-base 15786 df-sets 15787 df-ress 15788 df-plusg 15875 df-mulr 15876 df-starv 15877 df-sca 15878 df-vsca 15879 df-ip 15880 df-tset 15881 df-ple 15882 df-ds 15885 df-unif 15886 df-hom 15887 df-cco 15888 df-rest 16004 df-topn 16005 df-0g 16023 df-gsum 16024 df-topgen 16025 df-pt 16026 df-prds 16029 df-xrs 16083 df-qtop 16088 df-imas 16089 df-xps 16091 df-mre 16167 df-mrc 16168 df-acs 16170 df-mgm 17163 df-sgrp 17205 df-mnd 17216 df-submnd 17257 df-mulg 17462 df-cntz 17671 df-cmn 18116 df-psmet 19657 df-xmet 19658 df-met 19659 df-bl 19660 df-mopn 19661 df-fbas 19662 df-fg 19663 df-cnfld 19666 df-top 20621 df-bases 20622 df-topon 20623 df-topsp 20624 df-cld 20733 df-ntr 20734 df-cls 20735 df-nei 20812 df-lp 20850 df-perf 20851 df-cn 20941 df-cnp 20942 df-haus 21029 df-cmp 21100 df-tx 21275 df-hmeo 21468 df-fil 21560 df-fm 21652 df-flim 21653 df-flf 21654 df-xms 22035 df-ms 22036 df-tms 22037 df-cncf 22589 df-limc 23536 df-dv 23537

This theorem is referenced by: ioodvbdlimc1lem2 39453 ioodvbdlimc2lem 39455

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