Metamath Proof Explorer


Theorem plymulx0

Description: Coefficients of a polynomial multiplied by Xp . (Contributed by Thierry Arnoux, 25-Sep-2018)

Ref Expression
Assertion plymulx0
|- ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` ( F oF x. Xp ) ) = ( n e. NN0 |-> if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 eldifi
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> F e. ( Poly ` RR ) )
2 ax-resscn
 |-  RR C_ CC
3 1re
 |-  1 e. RR
4 plyid
 |-  ( ( RR C_ CC /\ 1 e. RR ) -> Xp e. ( Poly ` RR ) )
5 2 3 4 mp2an
 |-  Xp e. ( Poly ` RR )
6 5 a1i
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> Xp e. ( Poly ` RR ) )
7 simprl
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. RR /\ y e. RR ) ) -> x e. RR )
8 simprr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. RR /\ y e. RR ) ) -> y e. RR )
9 7 8 readdcld
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. RR /\ y e. RR ) ) -> ( x + y ) e. RR )
10 7 8 remulcld
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. RR /\ y e. RR ) ) -> ( x x. y ) e. RR )
11 1 6 9 10 plymul
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( F oF x. Xp ) e. ( Poly ` RR ) )
12 0re
 |-  0 e. RR
13 eqid
 |-  ( coeff ` ( F oF x. Xp ) ) = ( coeff ` ( F oF x. Xp ) )
14 13 coef2
 |-  ( ( ( F oF x. Xp ) e. ( Poly ` RR ) /\ 0 e. RR ) -> ( coeff ` ( F oF x. Xp ) ) : NN0 --> RR )
15 11 12 14 sylancl
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` ( F oF x. Xp ) ) : NN0 --> RR )
16 15 feqmptd
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` ( F oF x. Xp ) ) = ( n e. NN0 |-> ( ( coeff ` ( F oF x. Xp ) ) ` n ) ) )
17 cnex
 |-  CC e. _V
18 17 a1i
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> CC e. _V )
19 plyf
 |-  ( F e. ( Poly ` RR ) -> F : CC --> CC )
20 1 19 syl
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> F : CC --> CC )
21 plyf
 |-  ( Xp e. ( Poly ` RR ) -> Xp : CC --> CC )
22 5 21 ax-mp
 |-  Xp : CC --> CC
23 22 a1i
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> Xp : CC --> CC )
24 simprl
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. CC /\ y e. CC ) ) -> x e. CC )
25 simprr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. CC /\ y e. CC ) ) -> y e. CC )
26 24 25 mulcomd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ ( x e. CC /\ y e. CC ) ) -> ( x x. y ) = ( y x. x ) )
27 18 20 23 26 caofcom
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( F oF x. Xp ) = ( Xp oF x. F ) )
28 27 fveq2d
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` ( F oF x. Xp ) ) = ( coeff ` ( Xp oF x. F ) ) )
29 28 fveq1d
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( ( coeff ` ( F oF x. Xp ) ) ` n ) = ( ( coeff ` ( Xp oF x. F ) ) ` n ) )
30 29 adantr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> ( ( coeff ` ( F oF x. Xp ) ) ` n ) = ( ( coeff ` ( Xp oF x. F ) ) ` n ) )
31 5 a1i
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> Xp e. ( Poly ` RR ) )
32 1 adantr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> F e. ( Poly ` RR ) )
33 simpr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> n e. NN0 )
34 eqid
 |-  ( coeff ` Xp ) = ( coeff ` Xp )
35 eqid
 |-  ( coeff ` F ) = ( coeff ` F )
36 34 35 coemul
 |-  ( ( Xp e. ( Poly ` RR ) /\ F e. ( Poly ` RR ) /\ n e. NN0 ) -> ( ( coeff ` ( Xp oF x. F ) ) ` n ) = sum_ i e. ( 0 ... n ) ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) )
37 31 32 33 36 syl3anc
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> ( ( coeff ` ( Xp oF x. F ) ) ` n ) = sum_ i e. ( 0 ... n ) ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) )
38 elfznn0
 |-  ( i e. ( 0 ... n ) -> i e. NN0 )
39 coeidp
 |-  ( i e. NN0 -> ( ( coeff ` Xp ) ` i ) = if ( i = 1 , 1 , 0 ) )
40 38 39 syl
 |-  ( i e. ( 0 ... n ) -> ( ( coeff ` Xp ) ` i ) = if ( i = 1 , 1 , 0 ) )
41 40 oveq1d
 |-  ( i e. ( 0 ... n ) -> ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) = ( if ( i = 1 , 1 , 0 ) x. ( ( coeff ` F ) ` ( n - i ) ) ) )
42 ovif
 |-  ( if ( i = 1 , 1 , 0 ) x. ( ( coeff ` F ) ` ( n - i ) ) ) = if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) )
43 41 42 eqtrdi
 |-  ( i e. ( 0 ... n ) -> ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) = if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) )
44 43 adantl
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) = if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) )
45 44 sumeq2dv
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> sum_ i e. ( 0 ... n ) ( ( ( coeff ` Xp ) ` i ) x. ( ( coeff ` F ) ` ( n - i ) ) ) = sum_ i e. ( 0 ... n ) if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) )
46 velsn
 |-  ( i e. { 1 } <-> i = 1 )
47 46 bicomi
 |-  ( i = 1 <-> i e. { 1 } )
48 47 a1i
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( i = 1 <-> i e. { 1 } ) )
49 35 coef2
 |-  ( ( F e. ( Poly ` RR ) /\ 0 e. RR ) -> ( coeff ` F ) : NN0 --> RR )
50 1 12 49 sylancl
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` F ) : NN0 --> RR )
51 50 ad2antrr
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( coeff ` F ) : NN0 --> RR )
52 fznn0sub
 |-  ( i e. ( 0 ... n ) -> ( n - i ) e. NN0 )
53 52 adantl
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( n - i ) e. NN0 )
54 51 53 ffvelrnd
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( ( coeff ` F ) ` ( n - i ) ) e. RR )
55 54 recnd
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( ( coeff ` F ) ` ( n - i ) ) e. CC )
56 55 mulid2d
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) = ( ( coeff ` F ) ` ( n - i ) ) )
57 55 mul02d
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) = 0 )
58 48 56 57 ifbieq12d
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ i e. ( 0 ... n ) ) -> if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) = if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) )
59 58 sumeq2dv
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> sum_ i e. ( 0 ... n ) if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) = sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) )
60 eqeq2
 |-  ( 0 = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) -> ( sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = 0 <-> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) ) )
61 eqeq2
 |-  ( ( ( coeff ` F ) ` ( n - 1 ) ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) -> ( sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = ( ( coeff ` F ) ` ( n - 1 ) ) <-> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) ) )
62 oveq2
 |-  ( n = 0 -> ( 0 ... n ) = ( 0 ... 0 ) )
63 0z
 |-  0 e. ZZ
64 fzsn
 |-  ( 0 e. ZZ -> ( 0 ... 0 ) = { 0 } )
65 63 64 ax-mp
 |-  ( 0 ... 0 ) = { 0 }
66 62 65 eqtrdi
 |-  ( n = 0 -> ( 0 ... n ) = { 0 } )
67 elsni
 |-  ( i e. { 0 } -> i = 0 )
68 67 adantl
 |-  ( ( n = 0 /\ i e. { 0 } ) -> i = 0 )
69 ax-1ne0
 |-  1 =/= 0
70 69 nesymi
 |-  -. 0 = 1
71 eqeq1
 |-  ( i = 0 -> ( i = 1 <-> 0 = 1 ) )
72 70 71 mtbiri
 |-  ( i = 0 -> -. i = 1 )
73 68 72 syl
 |-  ( ( n = 0 /\ i e. { 0 } ) -> -. i = 1 )
74 47 notbii
 |-  ( -. i = 1 <-> -. i e. { 1 } )
75 74 biimpi
 |-  ( -. i = 1 -> -. i e. { 1 } )
76 iffalse
 |-  ( -. i e. { 1 } -> if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = 0 )
77 73 75 76 3syl
 |-  ( ( n = 0 /\ i e. { 0 } ) -> if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = 0 )
78 66 77 sumeq12rdv
 |-  ( n = 0 -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = sum_ i e. { 0 } 0 )
79 snfi
 |-  { 0 } e. Fin
80 79 olci
 |-  ( { 0 } C_ ( ZZ>= ` 0 ) \/ { 0 } e. Fin )
81 sumz
 |-  ( ( { 0 } C_ ( ZZ>= ` 0 ) \/ { 0 } e. Fin ) -> sum_ i e. { 0 } 0 = 0 )
82 80 81 ax-mp
 |-  sum_ i e. { 0 } 0 = 0
83 78 82 eqtrdi
 |-  ( n = 0 -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = 0 )
84 83 adantl
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ n = 0 ) -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = 0 )
85 simpll
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> F e. ( ( Poly ` RR ) \ { 0p } ) )
86 33 adantr
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> n e. NN0 )
87 simpr
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> -. n = 0 )
88 87 neqned
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> n =/= 0 )
89 elnnne0
 |-  ( n e. NN <-> ( n e. NN0 /\ n =/= 0 ) )
90 86 88 89 sylanbrc
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> n e. NN )
91 1nn0
 |-  1 e. NN0
92 91 a1i
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> 1 e. NN0 )
93 simpr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> n e. NN )
94 93 nnnn0d
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> n e. NN0 )
95 93 nnge1d
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> 1 <_ n )
96 elfz2nn0
 |-  ( 1 e. ( 0 ... n ) <-> ( 1 e. NN0 /\ n e. NN0 /\ 1 <_ n ) )
97 92 94 95 96 syl3anbrc
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> 1 e. ( 0 ... n ) )
98 97 snssd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> { 1 } C_ ( 0 ... n ) )
99 50 ad2antrr
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( coeff ` F ) : NN0 --> RR )
100 oveq2
 |-  ( i = 1 -> ( n - i ) = ( n - 1 ) )
101 46 100 sylbi
 |-  ( i e. { 1 } -> ( n - i ) = ( n - 1 ) )
102 101 adantl
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( n - i ) = ( n - 1 ) )
103 nnm1nn0
 |-  ( n e. NN -> ( n - 1 ) e. NN0 )
104 103 ad2antlr
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( n - 1 ) e. NN0 )
105 102 104 eqeltrd
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( n - i ) e. NN0 )
106 99 105 ffvelrnd
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( ( coeff ` F ) ` ( n - i ) ) e. RR )
107 106 recnd
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) /\ i e. { 1 } ) -> ( ( coeff ` F ) ` ( n - i ) ) e. CC )
108 107 ralrimiva
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> A. i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) e. CC )
109 fzfi
 |-  ( 0 ... n ) e. Fin
110 109 olci
 |-  ( ( 0 ... n ) C_ ( ZZ>= ` 0 ) \/ ( 0 ... n ) e. Fin )
111 110 a1i
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> ( ( 0 ... n ) C_ ( ZZ>= ` 0 ) \/ ( 0 ... n ) e. Fin ) )
112 sumss2
 |-  ( ( ( { 1 } C_ ( 0 ... n ) /\ A. i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) e. CC ) /\ ( ( 0 ... n ) C_ ( ZZ>= ` 0 ) \/ ( 0 ... n ) e. Fin ) ) -> sum_ i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) = sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) )
113 98 108 111 112 syl21anc
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> sum_ i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) = sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) )
114 50 adantr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> ( coeff ` F ) : NN0 --> RR )
115 103 adantl
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> ( n - 1 ) e. NN0 )
116 114 115 ffvelrnd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> ( ( coeff ` F ) ` ( n - 1 ) ) e. RR )
117 116 recnd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> ( ( coeff ` F ) ` ( n - 1 ) ) e. CC )
118 100 fveq2d
 |-  ( i = 1 -> ( ( coeff ` F ) ` ( n - i ) ) = ( ( coeff ` F ) ` ( n - 1 ) ) )
119 118 sumsn
 |-  ( ( 1 e. RR /\ ( ( coeff ` F ) ` ( n - 1 ) ) e. CC ) -> sum_ i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) = ( ( coeff ` F ) ` ( n - 1 ) ) )
120 3 117 119 sylancr
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> sum_ i e. { 1 } ( ( coeff ` F ) ` ( n - i ) ) = ( ( coeff ` F ) ` ( n - 1 ) ) )
121 113 120 eqtr3d
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN ) -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = ( ( coeff ` F ) ` ( n - 1 ) ) )
122 85 90 121 syl2anc
 |-  ( ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) /\ -. n = 0 ) -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = ( ( coeff ` F ) ` ( n - 1 ) ) )
123 60 61 84 122 ifbothda
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> sum_ i e. ( 0 ... n ) if ( i e. { 1 } , ( ( coeff ` F ) ` ( n - i ) ) , 0 ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) )
124 59 123 eqtrd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> sum_ i e. ( 0 ... n ) if ( i = 1 , ( 1 x. ( ( coeff ` F ) ` ( n - i ) ) ) , ( 0 x. ( ( coeff ` F ) ` ( n - i ) ) ) ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) )
125 37 45 124 3eqtrd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> ( ( coeff ` ( Xp oF x. F ) ) ` n ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) )
126 30 125 eqtrd
 |-  ( ( F e. ( ( Poly ` RR ) \ { 0p } ) /\ n e. NN0 ) -> ( ( coeff ` ( F oF x. Xp ) ) ` n ) = if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) )
127 126 mpteq2dva
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( n e. NN0 |-> ( ( coeff ` ( F oF x. Xp ) ) ` n ) ) = ( n e. NN0 |-> if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) ) )
128 16 127 eqtrd
 |-  ( F e. ( ( Poly ` RR ) \ { 0p } ) -> ( coeff ` ( F oF x. Xp ) ) = ( n e. NN0 |-> if ( n = 0 , 0 , ( ( coeff ` F ) ` ( n - 1 ) ) ) ) )