Theorem plycoeid3 15548

Description: Reconstruct a polynomial as an explicit sum of the coefficient function up to an index no smaller than the degree of the polynomial. (Contributed by Jim Kingdon, 17-Oct-2025.)

Hypotheses

Ref	Expression
plycoeid3.d	|- ( ph -> D e. NN0 )
plycoeid3.a	|- ( ph -> A : NN0 --> CC )
plycoeid3.z	|- ( ph -> ( A " ( ZZ>= ` ( D + 1 ) ) ) = { 0 } )
plycoeid3.f	|- ( ph -> F = ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) ) )
plycoeid3.m	|- ( ph -> M e. ( ZZ>= ` D ) )
plycoeid3.x	|- ( ph -> X e. CC )

Assertion

Ref	Expression
plycoeid3	|- ( ph -> ( F ` X ) = sum_ j e. ( 0 ... M ) ( ( A ` j ) x. ( X ^ j ) ) )

Distinct variable groups:   A, j, z   A, k, z   D, k, z   j, M   k, M   j, X, z   k, X

Allowed substitution hints:   ph( z, j, k)   D( j)   F( z, j, k)   M( z)

Proof of Theorem plycoeid3

Dummy variables r q p are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		plycoeid3.f	. . . . . 6 |- ( ph -> F = ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) ) )
2	1	fveq1d 5650	. . . . 5 |- ( ph -> ( F ` X ) = ( ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) ) ` X ) )
3		eqid 2231	. . . . . 6 |- ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) ) = ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) )
4		oveq1 6035	. . . . . . . 8 |- ( z = X -> ( z ^ k ) = ( X ^ k ) )
5	4	oveq2d 6044	. . . . . . 7 |- ( z = X -> ( ( A ` k ) x. ( z ^ k ) ) = ( ( A ` k ) x. ( X ^ k ) ) )
6	5	sumeq2sdv 11991	. . . . . 6 |- ( z = X -> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) = sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) ) )
7		plycoeid3.x	. . . . . 6 |- ( ph -> X e. CC )
8		fveq2 5648	. . . . . . . . 9 |- ( q = k -> ( A ` q ) = ( A ` k ) )
9		oveq2 6036	. . . . . . . . 9 |- ( q = k -> ( X ^ q ) = ( X ^ k ) )
10	8, 9	oveq12d 6046	. . . . . . . 8 |- ( q = k -> ( ( A ` q ) x. ( X ^ q ) ) = ( ( A ` k ) x. ( X ^ k ) ) )
11	10	cbvsumv 11982	. . . . . . 7 |- sum_ q e. ( 0 ... D ) ( ( A ` q ) x. ( X ^ q ) ) = sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) )
12		0zd 9534	. . . . . . . . 9 |- ( ph -> 0 e. ZZ )
13		plycoeid3.d	. . . . . . . . . 10 |- ( ph -> D e. NN0 )
14	13	nn0zd 9643	. . . . . . . . 9 |- ( ph -> D e. ZZ )
15	12, 14	fzfigd 10737	. . . . . . . 8 |- ( ph -> ( 0 ... D ) e. Fin )
16		plycoeid3.a	. . . . . . . . . . 11 |- ( ph -> A : NN0 --> CC )
17	16	adantr 276	. . . . . . . . . 10 |- ( ( ph /\ q e. ( 0 ... D ) ) -> A : NN0 --> CC )
18		elfznn0 10392	. . . . . . . . . . 11 |- ( q e. ( 0 ... D ) -> q e. NN0 )
19	18	adantl 277	. . . . . . . . . 10 |- ( ( ph /\ q e. ( 0 ... D ) ) -> q e. NN0 )
20	17, 19	ffvelcdmd 5791	. . . . . . . . 9 |- ( ( ph /\ q e. ( 0 ... D ) ) -> ( A ` q ) e. CC )
21	7	adantr 276	. . . . . . . . . 10 |- ( ( ph /\ q e. ( 0 ... D ) ) -> X e. CC )
22	21, 19	expcld 10979	. . . . . . . . 9 |- ( ( ph /\ q e. ( 0 ... D ) ) -> ( X ^ q ) e. CC )
23	20, 22	mulcld 8243	. . . . . . . 8 |- ( ( ph /\ q e. ( 0 ... D ) ) -> ( ( A ` q ) x. ( X ^ q ) ) e. CC )
24	15, 23	fsumcl 12022	. . . . . . 7 |- ( ph -> sum_ q e. ( 0 ... D ) ( ( A ` q ) x. ( X ^ q ) ) e. CC )
25	11, 24	eqeltrrid 2319	. . . . . 6 |- ( ph -> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) ) e. CC )
26	3, 6, 7, 25	fvmptd3 5749	. . . . 5 |- ( ph -> ( ( z e. CC |-> sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( z ^ k ) ) ) ` X ) = sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) ) )
27	2, 26	eqtrd 2264	. . . 4 |- ( ph -> ( F ` X ) = sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) ) )
28		fveq2 5648	. . . . . 6 |- ( k = r -> ( A ` k ) = ( A ` r ) )
29		oveq2 6036	. . . . . 6 |- ( k = r -> ( X ^ k ) = ( X ^ r ) )
30	28, 29	oveq12d 6046	. . . . 5 |- ( k = r -> ( ( A ` k ) x. ( X ^ k ) ) = ( ( A ` r ) x. ( X ^ r ) ) )
31	30	cbvsumv 11982	. . . 4 |- sum_ k e. ( 0 ... D ) ( ( A ` k ) x. ( X ^ k ) ) = sum_ r e. ( 0 ... D ) ( ( A ` r ) x. ( X ^ r ) )
32	27, 31	eqtrdi 2280	. . 3 |- ( ph -> ( F ` X ) = sum_ r e. ( 0 ... D ) ( ( A ` r ) x. ( X ^ r ) ) )
33		plycoeid3.m	. . . . 5 |- ( ph -> M e. ( ZZ>= ` D ) )
34		fzss2 10342	. . . . 5 |- ( M e. ( ZZ>= ` D ) -> ( 0 ... D ) C_ ( 0 ... M ) )
35	33, 34	syl 14	. . . 4 |- ( ph -> ( 0 ... D ) C_ ( 0 ... M ) )
36	16	adantr 276	. . . . . 6 |- ( ( ph /\ r e. ( 0 ... D ) ) -> A : NN0 --> CC )
37		elfznn0 10392	. . . . . . 7 |- ( r e. ( 0 ... D ) -> r e. NN0 )
38	37	adantl 277	. . . . . 6 |- ( ( ph /\ r e. ( 0 ... D ) ) -> r e. NN0 )
39	36, 38	ffvelcdmd 5791	. . . . 5 |- ( ( ph /\ r e. ( 0 ... D ) ) -> ( A ` r ) e. CC )
40	7	adantr 276	. . . . . 6 |- ( ( ph /\ r e. ( 0 ... D ) ) -> X e. CC )
41	40, 38	expcld 10979	. . . . 5 |- ( ( ph /\ r e. ( 0 ... D ) ) -> ( X ^ r ) e. CC )
42	39, 41	mulcld 8243	. . . 4 |- ( ( ph /\ r e. ( 0 ... D ) ) -> ( ( A ` r ) x. ( X ^ r ) ) e. CC )
43		eldifn 3332	. . . . . . . . . 10 |- ( r e. ( ( 0 ... M ) \ ( 0 ... D ) ) -> -. r e. ( 0 ... D ) )
44	43	adantl 277	. . . . . . . . 9 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> -. r e. ( 0 ... D ) )
45		eldifi 3331	. . . . . . . . . . . . . 14 |- ( r e. ( ( 0 ... M ) \ ( 0 ... D ) ) -> r e. ( 0 ... M ) )
46	45	adantl 277	. . . . . . . . . . . . 13 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> r e. ( 0 ... M ) )
47		elfznn0 10392	. . . . . . . . . . . . 13 |- ( r e. ( 0 ... M ) -> r e. NN0 )
48	46, 47	syl 14	. . . . . . . . . . . 12 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> r e. NN0 )
49		nn0split 10414	. . . . . . . . . . . . . 14 |- ( D e. NN0 -> NN0 = ( ( 0 ... D ) u. ( ZZ>= ` ( D + 1 ) ) ) )
50	13, 49	syl 14	. . . . . . . . . . . . 13 |- ( ph -> NN0 = ( ( 0 ... D ) u. ( ZZ>= ` ( D + 1 ) ) ) )
51	50	adantr 276	. . . . . . . . . . . 12 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> NN0 = ( ( 0 ... D ) u. ( ZZ>= ` ( D + 1 ) ) ) )
52	48, 51	eleqtrd 2310	. . . . . . . . . . 11 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> r e. ( ( 0 ... D ) u. ( ZZ>= ` ( D + 1 ) ) ) )
53		elun 3350	. . . . . . . . . . 11 |- ( r e. ( ( 0 ... D ) u. ( ZZ>= ` ( D + 1 ) ) ) <-> ( r e. ( 0 ... D ) \/ r e. ( ZZ>= ` ( D + 1 ) ) ) )
54	52, 53	sylib 122	. . . . . . . . . 10 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( r e. ( 0 ... D ) \/ r e. ( ZZ>= ` ( D + 1 ) ) ) )
55	54	orcomd 737	. . . . . . . . 9 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( r e. ( ZZ>= ` ( D + 1 ) ) \/ r e. ( 0 ... D ) ) )
56	44, 55	ecased 1386	. . . . . . . 8 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> r e. ( ZZ>= ` ( D + 1 ) ) )
57		plycoeid3.z	. . . . . . . . . . 11 |- ( ph -> ( A " ( ZZ>= ` ( D + 1 ) ) ) = { 0 } )
58		eqimss 3282	. . . . . . . . . . 11 |- ( ( A " ( ZZ>= ` ( D + 1 ) ) ) = { 0 } -> ( A " ( ZZ>= ` ( D + 1 ) ) ) C_ { 0 } )
59	57, 58	syl 14	. . . . . . . . . 10 |- ( ph -> ( A " ( ZZ>= ` ( D + 1 ) ) ) C_ { 0 } )
60	16	ffund 5493	. . . . . . . . . . 11 |- ( ph -> Fun A )
61		peano2nn0 9485	. . . . . . . . . . . . . . . 16 |- ( D e. NN0 -> ( D + 1 ) e. NN0 )
62	13, 61	syl 14	. . . . . . . . . . . . . . 15 |- ( ph -> ( D + 1 ) e. NN0 )
63		nn0uz 9834	. . . . . . . . . . . . . . 15 |- NN0 = ( ZZ>= ` 0 )
64	62, 63	eleqtrdi 2324	. . . . . . . . . . . . . 14 |- ( ph -> ( D + 1 ) e. ( ZZ>= ` 0 ) )
65		uzss 9820	. . . . . . . . . . . . . 14 |- ( ( D + 1 ) e. ( ZZ>= ` 0 ) -> ( ZZ>= ` ( D + 1 ) ) C_ ( ZZ>= ` 0 ) )
66	64, 65	syl 14	. . . . . . . . . . . . 13 |- ( ph -> ( ZZ>= ` ( D + 1 ) ) C_ ( ZZ>= ` 0 ) )
67	66, 63	sseqtrrdi 3277	. . . . . . . . . . . 12 |- ( ph -> ( ZZ>= ` ( D + 1 ) ) C_ NN0 )
68	16	fdmd 5496	. . . . . . . . . . . 12 |- ( ph -> dom A = NN0 )
69	67, 68	sseqtrrd 3267	. . . . . . . . . . 11 |- ( ph -> ( ZZ>= ` ( D + 1 ) ) C_ dom A )
70		funimass4 5705	. . . . . . . . . . 11 |- ( ( Fun A /\ ( ZZ>= ` ( D + 1 ) ) C_ dom A ) -> ( ( A " ( ZZ>= ` ( D + 1 ) ) ) C_ { 0 } <-> A. r e. ( ZZ>= ` ( D + 1 ) ) ( A ` r ) e. { 0 } ) )
71	60, 69, 70	syl2anc 411	. . . . . . . . . 10 |- ( ph -> ( ( A " ( ZZ>= ` ( D + 1 ) ) ) C_ { 0 } <-> A. r e. ( ZZ>= ` ( D + 1 ) ) ( A ` r ) e. { 0 } ) )
72	59, 71	mpbid 147	. . . . . . . . 9 |- ( ph -> A. r e. ( ZZ>= ` ( D + 1 ) ) ( A ` r ) e. { 0 } )
73	72	r19.21bi 2621	. . . . . . . 8 |- ( ( ph /\ r e. ( ZZ>= ` ( D + 1 ) ) ) -> ( A ` r ) e. { 0 } )
74	56, 73	syldan 282	. . . . . . 7 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( A ` r ) e. { 0 } )
75		elsni 3691	. . . . . . 7 |- ( ( A ` r ) e. { 0 } -> ( A ` r ) = 0 )
76	74, 75	syl 14	. . . . . 6 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( A ` r ) = 0 )
77	76	oveq1d 6043	. . . . 5 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( ( A ` r ) x. ( X ^ r ) ) = ( 0 x. ( X ^ r ) ) )
78	7	adantr 276	. . . . . . 7 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> X e. CC )
79	78, 48	expcld 10979	. . . . . 6 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( X ^ r ) e. CC )
80	79	mul02d 8614	. . . . 5 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( 0 x. ( X ^ r ) ) = 0 )
81	77, 80	eqtrd 2264	. . . 4 |- ( ( ph /\ r e. ( ( 0 ... M ) \ ( 0 ... D ) ) ) -> ( ( A ` r ) x. ( X ^ r ) ) = 0 )
82		elfzelz 10303	. . . . . . 7 |- ( p e. ( 0 ... M ) -> p e. ZZ )
83	82	adantl 277	. . . . . 6 |- ( ( ph /\ p e. ( 0 ... M ) ) -> p e. ZZ )
84		0zd 9534	. . . . . 6 |- ( ( ph /\ p e. ( 0 ... M ) ) -> 0 e. ZZ )
85	14	adantr 276	. . . . . 6 |- ( ( ph /\ p e. ( 0 ... M ) ) -> D e. ZZ )
86		fzdcel 10318	. . . . . 6 |- ( ( p e. ZZ /\ 0 e. ZZ /\ D e. ZZ ) -> DECID p e. ( 0 ... D ) )
87	83, 84, 85, 86	syl3anc 1274	. . . . 5 |- ( ( ph /\ p e. ( 0 ... M ) ) -> DECID p e. ( 0 ... D ) )
88	87	ralrimiva 2606	. . . 4 |- ( ph -> A. p e. ( 0 ... M )DECID p e. ( 0 ... D ) )
89		eluzelz 9808	. . . . . 6 |- ( M e. ( ZZ>= ` D ) -> M e. ZZ )
90	33, 89	syl 14	. . . . 5 |- ( ph -> M e. ZZ )
91	12, 90	fzfigd 10737	. . . 4 |- ( ph -> ( 0 ... M ) e. Fin )
92	35, 42, 81, 88, 91	fisumss 12014	. . 3 |- ( ph -> sum_ r e. ( 0 ... D ) ( ( A ` r ) x. ( X ^ r ) ) = sum_ r e. ( 0 ... M ) ( ( A ` r ) x. ( X ^ r ) ) )
93	32, 92	eqtrd 2264	. 2 |- ( ph -> ( F ` X ) = sum_ r e. ( 0 ... M ) ( ( A ` r ) x. ( X ^ r ) ) )
94		fveq2 5648	. . . 4 |- ( r = j -> ( A ` r ) = ( A ` j ) )
95		oveq2 6036	. . . 4 |- ( r = j -> ( X ^ r ) = ( X ^ j ) )
96	94, 95	oveq12d 6046	. . 3 |- ( r = j -> ( ( A ` r ) x. ( X ^ r ) ) = ( ( A ` j ) x. ( X ^ j ) ) )
97	96	cbvsumv 11982	. 2 |- sum_ r e. ( 0 ... M ) ( ( A ` r ) x. ( X ^ r ) ) = sum_ j e. ( 0 ... M ) ( ( A ` j ) x. ( X ^ j ) )
98	93, 97	eqtrdi 2280	1 |- ( ph -> ( F ` X ) = sum_ j e. ( 0 ... M ) ( ( A ` j ) x. ( X ^ j ) ) )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 104   <-> wb 105   \/ wo 716  DECID wdc 842   = wceq 1398   e. wcel 2202   A.wral 2511   \ cdif 3198   u. cun 3199   C_ wss 3201   {csn 3673   |-> cmpt 4155   dom cdm 4731   "cima 4734   Fun wfun 5327   -->wf 5329   ` cfv 5333  (class class class)co 6028   CCcc 8073   0cc0 8075   1c1 8076   + caddc 8078   x. cmul 8080   NN0cn0 9445   ZZcz 9522   ZZ>=cuz 9798   ...cfz 10286   ^cexp 10844   sum_csu 11974

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 619  ax-in2 620  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-13 2204  ax-14 2205  ax-ext 2213  ax-coll 4209  ax-sep 4212  ax-nul 4220  ax-pow 4270  ax-pr 4305  ax-un 4536  ax-setind 4641  ax-iinf 4692  ax-cnex 8166  ax-resscn 8167  ax-1cn 8168  ax-1re 8169  ax-icn 8170  ax-addcl 8171  ax-addrcl 8172  ax-mulcl 8173  ax-mulrcl 8174  ax-addcom 8175  ax-mulcom 8176  ax-addass 8177  ax-mulass 8178  ax-distr 8179  ax-i2m1 8180  ax-0lt1 8181  ax-1rid 8182  ax-0id 8183  ax-rnegex 8184  ax-precex 8185  ax-cnre 8186  ax-pre-ltirr 8187  ax-pre-ltwlin 8188  ax-pre-lttrn 8189  ax-pre-apti 8190  ax-pre-ltadd 8191  ax-pre-mulgt0 8192  ax-pre-mulext 8193  ax-arch 8194  ax-caucvg 8195

This theorem depends on definitions:  df-bi 117  df-dc 843  df-3or 1006  df-3an 1007  df-tru 1401  df-fal 1404  df-nf 1510  df-sb 1811  df-eu 2082  df-mo 2083  df-clab 2218  df-cleq 2224  df-clel 2227  df-nfc 2364  df-ne 2404  df-nel 2499  df-ral 2516  df-rex 2517  df-reu 2518  df-rmo 2519  df-rab 2520  df-v 2805  df-sbc 3033  df-csb 3129  df-dif 3203  df-un 3205  df-in 3207  df-ss 3214  df-nul 3497  df-if 3608  df-pw 3658  df-sn 3679  df-pr 3680  df-op 3682  df-uni 3899  df-int 3934  df-iun 3977  df-br 4094  df-opab 4156  df-mpt 4157  df-tr 4193  df-id 4396  df-po 4399  df-iso 4400  df-iord 4469  df-on 4471  df-ilim 4472  df-suc 4474  df-iom 4695  df-xp 4737  df-rel 4738  df-cnv 4739  df-co 4740  df-dm 4741  df-rn 4742  df-res 4743  df-ima 4744  df-iota 5293  df-fun 5335  df-fn 5336  df-f 5337  df-f1 5338  df-fo 5339  df-f1o 5340  df-fv 5341  df-isom 5342  df-riota 5981  df-ov 6031  df-oprab 6032  df-mpo 6033  df-1st 6312  df-2nd 6313  df-recs 6514  df-irdg 6579  df-frec 6600  df-1o 6625  df-oadd 6629  df-er 6745  df-en 6953  df-dom 6954  df-fin 6955  df-pnf 8259  df-mnf 8260  df-xr 8261  df-ltxr 8262  df-le 8263  df-sub 8395  df-neg 8396  df-reap 8798  df-ap 8805  df-div 8896  df-inn 9187  df-2 9245  df-3 9246  df-4 9247  df-n0 9446  df-z 9523  df-uz 9799  df-q 9897  df-rp 9932  df-fz 10287  df-fzo 10421  df-seqfrec 10754  df-exp 10845  df-ihash 11082  df-cj 11463  df-re 11464  df-im 11465  df-rsqrt 11619  df-abs 11620  df-clim 11900  df-sumdc 11975

This theorem is referenced by:  dvply2g  15557