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Theorem expcllem 10970

Description: Lemma for proving nonnegative integer exponentiation closure laws. (Contributed by NM, 14-Dec-2005.)

**Hypotheses**
Ref	Expression
expcllem.1	⊢ 𝐹 ⊆ ℂ
expcllem.2	⊢ ((𝑥 ∈ 𝐹 ∧ 𝑦 ∈ 𝐹) → (𝑥 · 𝑦) ∈ 𝐹)
expcllem.3	⊢ 1 ∈ 𝐹

**Assertion**
Ref	Expression
expcllem	⊢ ((𝐴 ∈ 𝐹 ∧ 𝐵 ∈ ℕ₀) → (𝐴↑𝐵) ∈ 𝐹)

Distinct variable groups: 𝑥,𝑦,𝐴 𝑥,𝐵 𝑥,𝐹,𝑦 Allowed substitution hint: 𝐵(𝑦)

Proof of Theorem expcllem Dummy variables 𝑧 𝑤 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		elnn0 9548	. 2 ⊢ (𝐵 ∈ ℕ₀ ↔ (𝐵 ∈ ℕ ∨ 𝐵 = 0))
2		oveq2 6087	. . . . . . 7 ⊢ (𝑧 = 1 → (𝐴↑𝑧) = (𝐴↑1))
3	2	eleq1d 2307	. . . . . 6 ⊢ (𝑧 = 1 → ((𝐴↑𝑧) ∈ 𝐹 ↔ (𝐴↑1) ∈ 𝐹))
4	3	imbi2d 230	. . . . 5 ⊢ (𝑧 = 1 → ((𝐴 ∈ 𝐹 → (𝐴↑𝑧) ∈ 𝐹) ↔ (𝐴 ∈ 𝐹 → (𝐴↑1) ∈ 𝐹)))
5		oveq2 6087	. . . . . . 7 ⊢ (𝑧 = 𝑤 → (𝐴↑𝑧) = (𝐴↑𝑤))
6	5	eleq1d 2307	. . . . . 6 ⊢ (𝑧 = 𝑤 → ((𝐴↑𝑧) ∈ 𝐹 ↔ (𝐴↑𝑤) ∈ 𝐹))
7	6	imbi2d 230	. . . . 5 ⊢ (𝑧 = 𝑤 → ((𝐴 ∈ 𝐹 → (𝐴↑𝑧) ∈ 𝐹) ↔ (𝐴 ∈ 𝐹 → (𝐴↑𝑤) ∈ 𝐹)))
8		oveq2 6087	. . . . . . 7 ⊢ (𝑧 = (𝑤 + 1) → (𝐴↑𝑧) = (𝐴↑(𝑤 + 1)))
9	8	eleq1d 2307	. . . . . 6 ⊢ (𝑧 = (𝑤 + 1) → ((𝐴↑𝑧) ∈ 𝐹 ↔ (𝐴↑(𝑤 + 1)) ∈ 𝐹))
10	9	imbi2d 230	. . . . 5 ⊢ (𝑧 = (𝑤 + 1) → ((𝐴 ∈ 𝐹 → (𝐴↑𝑧) ∈ 𝐹) ↔ (𝐴 ∈ 𝐹 → (𝐴↑(𝑤 + 1)) ∈ 𝐹)))
11		oveq2 6087	. . . . . . 7 ⊢ (𝑧 = 𝐵 → (𝐴↑𝑧) = (𝐴↑𝐵))
12	11	eleq1d 2307	. . . . . 6 ⊢ (𝑧 = 𝐵 → ((𝐴↑𝑧) ∈ 𝐹 ↔ (𝐴↑𝐵) ∈ 𝐹))
13	12	imbi2d 230	. . . . 5 ⊢ (𝑧 = 𝐵 → ((𝐴 ∈ 𝐹 → (𝐴↑𝑧) ∈ 𝐹) ↔ (𝐴 ∈ 𝐹 → (𝐴↑𝐵) ∈ 𝐹)))
14		expcllem.1	. . . . . . . . 9 ⊢ 𝐹 ⊆ ℂ
15	14	sseli 3244	. . . . . . . 8 ⊢ (𝐴 ∈ 𝐹 → 𝐴 ∈ ℂ)
16		exp1 10965	. . . . . . . 8 ⊢ (𝐴 ∈ ℂ → (𝐴↑1) = 𝐴)
17	15, 16	syl 14	. . . . . . 7 ⊢ (𝐴 ∈ 𝐹 → (𝐴↑1) = 𝐴)
18	17	eleq1d 2307	. . . . . 6 ⊢ (𝐴 ∈ 𝐹 → ((𝐴↑1) ∈ 𝐹 ↔ 𝐴 ∈ 𝐹))
19	18	ibir 177	. . . . 5 ⊢ (𝐴 ∈ 𝐹 → (𝐴↑1) ∈ 𝐹)
20		expcllem.2	. . . . . . . . . . . 12 ⊢ ((𝑥 ∈ 𝐹 ∧ 𝑦 ∈ 𝐹) → (𝑥 · 𝑦) ∈ 𝐹)
21	20	caovcl 6238	. . . . . . . . . . 11 ⊢ (((𝐴↑𝑤) ∈ 𝐹 ∧ 𝐴 ∈ 𝐹) → ((𝐴↑𝑤) · 𝐴) ∈ 𝐹)
22	21	ancoms 268	. . . . . . . . . 10 ⊢ ((𝐴 ∈ 𝐹 ∧ (𝐴↑𝑤) ∈ 𝐹) → ((𝐴↑𝑤) · 𝐴) ∈ 𝐹)
23	22	adantlr 481	. . . . . . . . 9 ⊢ (((𝐴 ∈ 𝐹 ∧ 𝑤 ∈ ℕ) ∧ (𝐴↑𝑤) ∈ 𝐹) → ((𝐴↑𝑤) · 𝐴) ∈ 𝐹)
24		nnnn0 9553	. . . . . . . . . . . 12 ⊢ (𝑤 ∈ ℕ → 𝑤 ∈ ℕ₀)
25		expp1 10966	. . . . . . . . . . . 12 ⊢ ((𝐴 ∈ ℂ ∧ 𝑤 ∈ ℕ₀) → (𝐴↑(𝑤 + 1)) = ((𝐴↑𝑤) · 𝐴))
26	15, 24, 25	syl2an 289	. . . . . . . . . . 11 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝑤 ∈ ℕ) → (𝐴↑(𝑤 + 1)) = ((𝐴↑𝑤) · 𝐴))
27	26	eleq1d 2307	. . . . . . . . . 10 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝑤 ∈ ℕ) → ((𝐴↑(𝑤 + 1)) ∈ 𝐹 ↔ ((𝐴↑𝑤) · 𝐴) ∈ 𝐹))
28	27	adantr 276	. . . . . . . . 9 ⊢ (((𝐴 ∈ 𝐹 ∧ 𝑤 ∈ ℕ) ∧ (𝐴↑𝑤) ∈ 𝐹) → ((𝐴↑(𝑤 + 1)) ∈ 𝐹 ↔ ((𝐴↑𝑤) · 𝐴) ∈ 𝐹))
29	23, 28	mpbird 167	. . . . . . . 8 ⊢ (((𝐴 ∈ 𝐹 ∧ 𝑤 ∈ ℕ) ∧ (𝐴↑𝑤) ∈ 𝐹) → (𝐴↑(𝑤 + 1)) ∈ 𝐹)
30	29	exp31 364	. . . . . . 7 ⊢ (𝐴 ∈ 𝐹 → (𝑤 ∈ ℕ → ((𝐴↑𝑤) ∈ 𝐹 → (𝐴↑(𝑤 + 1)) ∈ 𝐹)))
31	30	com12 30	. . . . . 6 ⊢ (𝑤 ∈ ℕ → (𝐴 ∈ 𝐹 → ((𝐴↑𝑤) ∈ 𝐹 → (𝐴↑(𝑤 + 1)) ∈ 𝐹)))
32	31	a2d 26	. . . . 5 ⊢ (𝑤 ∈ ℕ → ((𝐴 ∈ 𝐹 → (𝐴↑𝑤) ∈ 𝐹) → (𝐴 ∈ 𝐹 → (𝐴↑(𝑤 + 1)) ∈ 𝐹)))
33	4, 7, 10, 13, 19, 32	nnind 9303	. . . 4 ⊢ (𝐵 ∈ ℕ → (𝐴 ∈ 𝐹 → (𝐴↑𝐵) ∈ 𝐹))
34	33	impcom 125	. . 3 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝐵 ∈ ℕ) → (𝐴↑𝐵) ∈ 𝐹)
35		oveq2 6087	. . . . 5 ⊢ (𝐵 = 0 → (𝐴↑𝐵) = (𝐴↑0))
36		exp0 10963	. . . . . 6 ⊢ (𝐴 ∈ ℂ → (𝐴↑0) = 1)
37	15, 36	syl 14	. . . . 5 ⊢ (𝐴 ∈ 𝐹 → (𝐴↑0) = 1)
38	35, 37	sylan9eqr 2293	. . . 4 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝐵 = 0) → (𝐴↑𝐵) = 1)
39		expcllem.3	. . . 4 ⊢ 1 ∈ 𝐹
40	38, 39	eqeltrdi 2329	. . 3 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝐵 = 0) → (𝐴↑𝐵) ∈ 𝐹)
41	34, 40	jaodan 809	. 2 ⊢ ((𝐴 ∈ 𝐹 ∧ (𝐵 ∈ ℕ ∨ 𝐵 = 0)) → (𝐴↑𝐵) ∈ 𝐹)
42	1, 41	sylan2b 287	1 ⊢ ((𝐴 ∈ 𝐹 ∧ 𝐵 ∈ ℕ₀) → (𝐴↑𝐵) ∈ 𝐹)

Colors of variables: wff set class

Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 ∨ wo 720 = wceq 1402 ∈ wcel 2209 ⊆ wss 3220 (class class class)co 6079 ℂcc 8171 0cc0 8173 1c1 8174 + caddc 8176 · cmul 8178 ℕcn 9287 ℕ₀cn0 9546 ↑cexp 10958

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 623 ax-in2 624 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-coll 4244 ax-sep 4247 ax-nul 4257 ax-pow 4309 ax-pr 4344 ax-un 4576 ax-setind 4682 ax-iinf 4733 ax-cnex 8264 ax-resscn 8265 ax-1cn 8266 ax-1re 8267 ax-icn 8268 ax-addcl 8269 ax-addrcl 8270 ax-mulcl 8271 ax-mulrcl 8272 ax-addcom 8273 ax-mulcom 8274 ax-addass 8275 ax-mulass 8276 ax-distr 8277 ax-i2m1 8278 ax-0lt1 8279 ax-1rid 8280 ax-0id 8281 ax-rnegex 8282 ax-precex 8283 ax-cnre 8284 ax-pre-ltirr 8285 ax-pre-ltwlin 8286 ax-pre-lttrn 8287 ax-pre-apti 8288 ax-pre-ltadd 8289 ax-pre-mulgt0 8290 ax-pre-mulext 8291

This theorem depends on definitions: df-bi 117 df-dc 847 df-3or 1010 df-3an 1011 df-tru 1405 df-fal 1408 df-nf 1514 df-sb 1816 df-eu 2089 df-mo 2090 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ne 2421 df-nel 2516 df-ral 2533 df-rex 2534 df-reu 2535 df-rmo 2536 df-rab 2537 df-v 2823 df-sbc 3052 df-csb 3148 df-dif 3222 df-un 3224 df-in 3226 df-ss 3233 df-nul 3521 df-if 3639 df-pw 3690 df-sn 3714 df-pr 3715 df-op 3717 df-uni 3934 df-int 3969 df-iun 4012 df-br 4129 df-opab 4191 df-mpt 4192 df-tr 4228 df-id 4436 df-po 4439 df-iso 4440 df-iord 4509 df-on 4511 df-ilim 4512 df-suc 4514 df-iom 4736 df-xp 4778 df-rel 4779 df-cnv 4780 df-co 4781 df-dm 4782 df-rn 4783 df-res 4784 df-ima 4785 df-iota 5335 df-fun 5377 df-fn 5378 df-f 5379 df-f1 5380 df-fo 5381 df-f1o 5382 df-fv 5383 df-riota 6032 df-ov 6082 df-oprab 6083 df-mpo 6084 df-1st 6368 df-2nd 6369 df-recs 6570 df-frec 6656 df-pnf 8356 df-mnf 8357 df-xr 8358 df-ltxr 8359 df-le 8360 df-sub 8493 df-neg 8494 df-reap 8897 df-ap 8904 df-div 8997 df-inn 9288 df-n0 9547 df-z 9628 df-uz 9905 df-seqfrec 10868 df-exp 10959

This theorem is referenced by: expcl2lemap 10971 nnexpcl 10972 nn0expcl 10973 zexpcl 10974 qexpcl 10975 reexpcl 10976 expcl 10977 expge0 10995 expge1 10996 lgsfcl2 16108

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