dvcnp - Metamath Proof Explorer

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Theorem dvcnp 25893

Description: The difference quotient is continuous at 𝐵 when the original function is differentiable at 𝐵. (Contributed by Mario Carneiro, 8-Aug-2014.) (Revised by Mario Carneiro, 28-Dec-2016.)

**Hypotheses**
Ref	Expression
dvcnp.j	⊢ 𝐽 = (𝐾 ↾_t 𝐴)
dvcnp.k	⊢ 𝐾 = (TopOpen‘ℂ_fld)
dvcnp.g	⊢ 𝐺 = (𝑧 ∈ 𝐴 ↦ if(𝑧 = 𝐵, ((𝑆 D 𝐹)‘𝐵), (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))))

**Assertion**
Ref	Expression
dvcnp	⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → 𝐺 ∈ ((𝐽 CnP 𝐾)‘𝐵))

Distinct variable groups: 𝑧,𝐴 𝑧,𝐵 𝑧,𝐹 𝑧,𝐾 𝑧,𝑆 𝑧,𝐽 Allowed substitution hint: 𝐺(𝑧)

**Proof of Theorem dvcnp**
Step	Hyp	Ref	Expression
1		dvcnp.g	. 2 ⊢ 𝐺 = (𝑧 ∈ 𝐴 ↦ if(𝑧 = 𝐵, ((𝑆 D 𝐹)‘𝐵), (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))))
2		dvfg 25880	. . . . . . 7 ⊢ (𝑆 ∈ {ℝ, ℂ} → (𝑆 D 𝐹):dom (𝑆 D 𝐹)⟶ℂ)
3	2	3ad2ant1 1134	. . . . . 6 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → (𝑆 D 𝐹):dom (𝑆 D 𝐹)⟶ℂ)
4		ffun 6675	. . . . . 6 ⊢ ((𝑆 D 𝐹):dom (𝑆 D 𝐹)⟶ℂ → Fun (𝑆 D 𝐹))
5		funfvbrb 7007	. . . . . 6 ⊢ (Fun (𝑆 D 𝐹) → (𝐵 ∈ dom (𝑆 D 𝐹) ↔ 𝐵(𝑆 D 𝐹)((𝑆 D 𝐹)‘𝐵)))
6	3, 4, 5	3syl 18	. . . . 5 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → (𝐵 ∈ dom (𝑆 D 𝐹) ↔ 𝐵(𝑆 D 𝐹)((𝑆 D 𝐹)‘𝐵)))
7		eqid 2737	. . . . . 6 ⊢ (𝐾 ↾_t 𝑆) = (𝐾 ↾_t 𝑆)
8		dvcnp.k	. . . . . 6 ⊢ 𝐾 = (TopOpen‘ℂ_fld)
9		eqid 2737	. . . . . 6 ⊢ (𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))) = (𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵)))
10		recnprss 25878	. . . . . . 7 ⊢ (𝑆 ∈ {ℝ, ℂ} → 𝑆 ⊆ ℂ)
11	10	3ad2ant1 1134	. . . . . 6 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → 𝑆 ⊆ ℂ)
12		simp2 1138	. . . . . 6 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → 𝐹:𝐴⟶ℂ)
13		simp3 1139	. . . . . 6 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → 𝐴 ⊆ 𝑆)
14	7, 8, 9, 11, 12, 13	eldv 25872	. . . . 5 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → (𝐵(𝑆 D 𝐹)((𝑆 D 𝐹)‘𝐵) ↔ (𝐵 ∈ ((int‘(𝐾 ↾_t 𝑆))‘𝐴) ∧ ((𝑆 D 𝐹)‘𝐵) ∈ ((𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))) lim_ℂ 𝐵))))
15	6, 14	bitrd 279	. . . 4 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → (𝐵 ∈ dom (𝑆 D 𝐹) ↔ (𝐵 ∈ ((int‘(𝐾 ↾_t 𝑆))‘𝐴) ∧ ((𝑆 D 𝐹)‘𝐵) ∈ ((𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))) lim_ℂ 𝐵))))
16	15	simplbda 499	. . 3 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → ((𝑆 D 𝐹)‘𝐵) ∈ ((𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))) lim_ℂ 𝐵))
17	13, 11	sstrd 3946	. . . . 5 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → 𝐴 ⊆ ℂ)
18	17	adantr 480	. . . 4 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → 𝐴 ⊆ ℂ)
19	11, 12, 13	dvbss 25875	. . . . 5 ⊢ ((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) → dom (𝑆 D 𝐹) ⊆ 𝐴)
20	19	sselda 3935	. . . 4 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → 𝐵 ∈ 𝐴)
21		eldifsn 4744	. . . . 5 ⊢ (𝑧 ∈ (𝐴 ∖ {𝐵}) ↔ (𝑧 ∈ 𝐴 ∧ 𝑧 ≠ 𝐵))
22	12	adantr 480	. . . . . 6 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → 𝐹:𝐴⟶ℂ)
23	22, 18, 20	dvlem 25870	. . . . 5 ⊢ ((((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) ∧ 𝑧 ∈ (𝐴 ∖ {𝐵})) → (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵)) ∈ ℂ)
24	21, 23	sylan2br 596	. . . 4 ⊢ ((((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) ∧ (𝑧 ∈ 𝐴 ∧ 𝑧 ≠ 𝐵)) → (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵)) ∈ ℂ)
25		dvcnp.j	. . . 4 ⊢ 𝐽 = (𝐾 ↾_t 𝐴)
26	18, 20, 24, 25, 8	limcmpt2 25858	. . 3 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → (((𝑆 D 𝐹)‘𝐵) ∈ ((𝑧 ∈ (𝐴 ∖ {𝐵}) ↦ (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵))) lim_ℂ 𝐵) ↔ (𝑧 ∈ 𝐴 ↦ if(𝑧 = 𝐵, ((𝑆 D 𝐹)‘𝐵), (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵)))) ∈ ((𝐽 CnP 𝐾)‘𝐵)))
27	16, 26	mpbid 232	. 2 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → (𝑧 ∈ 𝐴 ↦ if(𝑧 = 𝐵, ((𝑆 D 𝐹)‘𝐵), (((𝐹‘𝑧) − (𝐹‘𝐵)) / (𝑧 − 𝐵)))) ∈ ((𝐽 CnP 𝐾)‘𝐵))
28	1, 27	eqeltrid 2841	1 ⊢ (((𝑆 ∈ {ℝ, ℂ} ∧ 𝐹:𝐴⟶ℂ ∧ 𝐴 ⊆ 𝑆) ∧ 𝐵 ∈ dom (𝑆 D 𝐹)) → 𝐺 ∈ ((𝐽 CnP 𝐾)‘𝐵))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 ∧ w3a 1087 = wceq 1542 ∈ wcel 2114 ≠ wne 2933 ∖ cdif 3900 ⊆ wss 3903 ifcif 4481 {csn 4582 {cpr 4584 class class class wbr 5100 ↦ cmpt 5181 dom cdm 5634 Fun wfun 6496 ⟶wf 6498 ‘cfv 6502 (class class class)co 7370 ℂcc 11038 ℝcr 11039 − cmin 11378 / cdiv 11808 ↾_t crest 17354 TopOpenctopn 17355 ℂ_fldccnfld 21326 intcnt 22978 CnP ccnp 23186 lim_ℂ climc 25836 D cdv 25837

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-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-tp 4587 df-op 4589 df-uni 4866 df-int 4905 df-iun 4950 df-iin 4951 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-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-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-er 8647 df-map 8779 df-pm 8780 df-en 8898 df-dom 8899 df-sdom 8900 df-fin 8901 df-fi 9328 df-sup 9359 df-inf 9360 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-4 12224 df-5 12225 df-6 12226 df-7 12227 df-8 12228 df-9 12229 df-n0 12416 df-z 12503 df-dec 12622 df-uz 12766 df-q 12876 df-rp 12920 df-xneg 13040 df-xadd 13041 df-xmul 13042 df-icc 13282 df-fz 13438 df-seq 13939 df-exp 13999 df-cj 15036 df-re 15037 df-im 15038 df-sqrt 15172 df-abs 15173 df-struct 17088 df-slot 17123 df-ndx 17135 df-base 17151 df-plusg 17204 df-mulr 17205 df-starv 17206 df-tset 17210 df-ple 17211 df-ds 17213 df-unif 17214 df-rest 17356 df-topn 17357 df-topgen 17377 df-psmet 21318 df-xmet 21319 df-met 21320 df-bl 21321 df-mopn 21322 df-fbas 21323 df-fg 21324 df-cnfld 21327 df-top 22855 df-topon 22872 df-topsp 22894 df-bases 22907 df-cld 22980 df-ntr 22981 df-cls 22982 df-nei 23059 df-lp 23097 df-perf 23098 df-cnp 23189 df-haus 23276 df-fil 23807 df-fm 23899 df-flim 23900 df-flf 23901 df-xms 24281 df-ms 24282 df-limc 25840 df-dv 25841

This theorem is referenced by: efrlim 26952 efrlimOLD 26953

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