Metamath Proof Explorer


Theorem fourierdlem113

Description: Fourier series convergence for periodic, piecewise smooth functions. (Contributed by Glauco Siliprandi, 11-Dec-2019)

Ref Expression
Hypotheses fourierdlem113.f φ F :
fourierdlem113.t T = 2 π
fourierdlem113.per φ x F x + T = F x
fourierdlem113.x φ X
fourierdlem113.l φ L F −∞ X lim X
fourierdlem113.r φ R F X +∞ lim X
fourierdlem113.p P = n p 0 n | p 0 = π p n = π i 0 ..^ n p i < p i + 1
fourierdlem113.m φ M
fourierdlem113.q φ Q P M
fourierdlem113.dvcn φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1 cn
fourierdlem113.dvlb φ i 0 ..^ M F Q i Q i + 1 lim Q i
fourierdlem113.dvub φ i 0 ..^ M F Q i Q i + 1 lim Q i + 1
fourierdlem113.a A = n 0 π π F x cos n x dx π
fourierdlem113.b B = n π π F x sin n x dx π
fourierdlem113.15 S = n A n cos n X + B n sin n X
fourierdlem113.e E = x x + π x T T
fourierdlem113.exq φ E X ran Q
Assertion fourierdlem113 φ seq 1 + S L + R 2 A 0 2 A 0 2 + n A n cos n X + B n sin n X = L + R 2

Proof

Step Hyp Ref Expression
1 fourierdlem113.f φ F :
2 fourierdlem113.t T = 2 π
3 fourierdlem113.per φ x F x + T = F x
4 fourierdlem113.x φ X
5 fourierdlem113.l φ L F −∞ X lim X
6 fourierdlem113.r φ R F X +∞ lim X
7 fourierdlem113.p P = n p 0 n | p 0 = π p n = π i 0 ..^ n p i < p i + 1
8 fourierdlem113.m φ M
9 fourierdlem113.q φ Q P M
10 fourierdlem113.dvcn φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1 cn
11 fourierdlem113.dvlb φ i 0 ..^ M F Q i Q i + 1 lim Q i
12 fourierdlem113.dvub φ i 0 ..^ M F Q i Q i + 1 lim Q i + 1
13 fourierdlem113.a A = n 0 π π F x cos n x dx π
14 fourierdlem113.b B = n π π F x sin n x dx π
15 fourierdlem113.15 S = n A n cos n X + B n sin n X
16 fourierdlem113.e E = x x + π x T T
17 fourierdlem113.exq φ E X ran Q
18 oveq1 w = y w mod 2 π = y mod 2 π
19 18 eqeq1d w = y w mod 2 π = 0 y mod 2 π = 0
20 oveq2 w = y k + 1 2 w = k + 1 2 y
21 20 fveq2d w = y sin k + 1 2 w = sin k + 1 2 y
22 fvoveq1 w = y sin w 2 = sin y 2
23 22 oveq2d w = y 2 π sin w 2 = 2 π sin y 2
24 21 23 oveq12d w = y sin k + 1 2 w 2 π sin w 2 = sin k + 1 2 y 2 π sin y 2
25 19 24 ifbieq2d w = y if w mod 2 π = 0 2 k + 1 2 π sin k + 1 2 w 2 π sin w 2 = if y mod 2 π = 0 2 k + 1 2 π sin k + 1 2 y 2 π sin y 2
26 25 cbvmptv w if w mod 2 π = 0 2 k + 1 2 π sin k + 1 2 w 2 π sin w 2 = y if y mod 2 π = 0 2 k + 1 2 π sin k + 1 2 y 2 π sin y 2
27 oveq2 k = m 2 k = 2 m
28 27 oveq1d k = m 2 k + 1 = 2 m + 1
29 28 oveq1d k = m 2 k + 1 2 π = 2 m + 1 2 π
30 oveq1 k = m k + 1 2 = m + 1 2
31 30 fvoveq1d k = m sin k + 1 2 y = sin m + 1 2 y
32 31 oveq1d k = m sin k + 1 2 y 2 π sin y 2 = sin m + 1 2 y 2 π sin y 2
33 29 32 ifeq12d k = m if y mod 2 π = 0 2 k + 1 2 π sin k + 1 2 y 2 π sin y 2 = if y mod 2 π = 0 2 m + 1 2 π sin m + 1 2 y 2 π sin y 2
34 33 mpteq2dv k = m y if y mod 2 π = 0 2 k + 1 2 π sin k + 1 2 y 2 π sin y 2 = y if y mod 2 π = 0 2 m + 1 2 π sin m + 1 2 y 2 π sin y 2
35 26 34 eqtrid k = m w if w mod 2 π = 0 2 k + 1 2 π sin k + 1 2 w 2 π sin w 2 = y if y mod 2 π = 0 2 m + 1 2 π sin m + 1 2 y 2 π sin y 2
36 35 cbvmptv k w if w mod 2 π = 0 2 k + 1 2 π sin k + 1 2 w 2 π sin w 2 = m y if y mod 2 π = 0 2 m + 1 2 π sin m + 1 2 y 2 π sin y 2
37 oveq1 w = y w + j T = y + j T
38 37 eleq1d w = y w + j T ran Q y + j T ran Q
39 38 rexbidv w = y j w + j T ran Q j y + j T ran Q
40 39 cbvrabv w - π + X π + X | j w + j T ran Q = y - π + X π + X | j y + j T ran Q
41 40 uneq2i - π + X π + X w - π + X π + X | j w + j T ran Q = - π + X π + X y - π + X π + X | j y + j T ran Q
42 41 fveq2i - π + X π + X w - π + X π + X | j w + j T ran Q = - π + X π + X y - π + X π + X | j y + j T ran Q
43 42 oveq1i - π + X π + X w - π + X π + X | j w + j T ran Q 1 = - π + X π + X y - π + X π + X | j y + j T ran Q 1
44 oveq1 k = j k T = j T
45 44 oveq2d k = j y + k T = y + j T
46 45 eleq1d k = j y + k T ran Q y + j T ran Q
47 46 cbvrexvw k y + k T ran Q j y + j T ran Q
48 47 rabbii y - π + X π + X | k y + k T ran Q = y - π + X π + X | j y + j T ran Q
49 48 uneq2i - π + X π + X y - π + X π + X | k y + k T ran Q = - π + X π + X y - π + X π + X | j y + j T ran Q
50 isoeq5 - π + X π + X y - π + X π + X | k y + k T ran Q = - π + X π + X y - π + X π + X | j y + j T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
51 49 50 ax-mp g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
52 51 a1i g = f g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
53 44 oveq2d k = j w + k T = w + j T
54 53 eleq1d k = j w + k T ran Q w + j T ran Q
55 54 cbvrexvw k w + k T ran Q j w + j T ran Q
56 55 rabbii w - π + X π + X | k w + k T ran Q = w - π + X π + X | j w + j T ran Q
57 56 uneq2i - π + X π + X w - π + X π + X | k w + k T ran Q = - π + X π + X w - π + X π + X | j w + j T ran Q
58 57 fveq2i - π + X π + X w - π + X π + X | k w + k T ran Q = - π + X π + X w - π + X π + X | j w + j T ran Q
59 58 oveq1i - π + X π + X w - π + X π + X | k w + k T ran Q 1 = - π + X π + X w - π + X π + X | j w + j T ran Q 1
60 59 oveq2i 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 = 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1
61 isoeq4 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 = 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
62 60 61 ax-mp g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
63 62 a1i g = f g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q g Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
64 isoeq1 g = f g Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
65 52 63 64 3bitrd g = f g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
66 65 cbviotavw ι g | g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q = ι f | f Isom < , < 0 - π + X π + X w - π + X π + X | j w + j T ran Q 1 - π + X π + X y - π + X π + X | j y + j T ran Q
67 pire π
68 67 renegcli π
69 68 a1i φ π
70 67 a1i φ π
71 negpilt0 π < 0
72 71 a1i φ π < 0
73 pipos 0 < π
74 73 a1i φ 0 < π
75 picn π
76 75 2timesi 2 π = π + π
77 75 75 subnegi π π = π + π
78 76 2 77 3eqtr4i T = π π
79 7 fourierdlem2 M Q P M Q 0 M Q 0 = π Q M = π i 0 ..^ M Q i < Q i + 1
80 8 79 syl φ Q P M Q 0 M Q 0 = π Q M = π i 0 ..^ M Q i < Q i + 1
81 9 80 mpbid φ Q 0 M Q 0 = π Q M = π i 0 ..^ M Q i < Q i + 1
82 81 simpld φ Q 0 M
83 elmapi Q 0 M Q : 0 M
84 82 83 syl φ Q : 0 M
85 fzfid φ 0 M Fin
86 rnffi Q : 0 M 0 M Fin ran Q Fin
87 84 85 86 syl2anc φ ran Q Fin
88 7 8 9 fourierdlem15 φ Q : 0 M π π
89 88 frnd φ ran Q π π
90 81 simprd φ Q 0 = π Q M = π i 0 ..^ M Q i < Q i + 1
91 90 simplrd φ Q M = π
92 88 ffund φ Fun Q
93 8 nnnn0d φ M 0
94 nn0uz 0 = 0
95 93 94 eleqtrdi φ M 0
96 eluzfz2 M 0 M 0 M
97 95 96 syl φ M 0 M
98 88 fdmd φ dom Q = 0 M
99 98 eqcomd φ 0 M = dom Q
100 97 99 eleqtrd φ M dom Q
101 fvelrn Fun Q M dom Q Q M ran Q
102 92 100 101 syl2anc φ Q M ran Q
103 91 102 eqeltrrd φ π ran Q
104 eqid - π + X π + X w - π + X π + X | k w + k T ran Q = - π + X π + X w - π + X π + X | k w + k T ran Q
105 isoeq1 g = f g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q
106 41 57 49 3eqtr4ri - π + X π + X y - π + X π + X | k y + k T ran Q = - π + X π + X w - π + X π + X | k w + k T ran Q
107 isoeq5 - π + X π + X y - π + X π + X | k y + k T ran Q = - π + X π + X w - π + X π + X | k w + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X w - π + X π + X | k w + k T ran Q
108 106 107 ax-mp f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X w - π + X π + X | k w + k T ran Q
109 105 108 bitrdi g = f g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X w - π + X π + X | k w + k T ran Q
110 109 cbviotavw ι g | g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q = ι f | f Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X w - π + X π + X | k w + k T ran Q
111 eqid w - π + X π + X | k w + k T ran Q = w - π + X π + X | k w + k T ran Q
112 69 70 72 74 78 87 89 103 16 4 17 104 110 111 fourierdlem51 φ X ran ι g | g Isom < , < 0 - π + X π + X w - π + X π + X | k w + k T ran Q 1 - π + X π + X y - π + X π + X | k y + k T ran Q
113 ax-resscn
114 113 a1i φ i 0 ..^ M
115 ioossre Q i Q i + 1
116 115 a1i φ Q i Q i + 1
117 1 116 fssresd φ F Q i Q i + 1 : Q i Q i + 1
118 113 a1i φ
119 117 118 fssd φ F Q i Q i + 1 : Q i Q i + 1
120 119 adantr φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1
121 115 a1i φ i 0 ..^ M Q i Q i + 1
122 1 118 fssd φ F :
123 122 adantr φ i 0 ..^ M F :
124 ssidd φ i 0 ..^ M
125 eqid TopOpen fld = TopOpen fld
126 tgioo4 topGen ran . = TopOpen fld 𝑡
127 125 126 dvres F : Q i Q i + 1 D F Q i Q i + 1 = F int topGen ran . Q i Q i + 1
128 114 123 124 121 127 syl22anc φ i 0 ..^ M D F Q i Q i + 1 = F int topGen ran . Q i Q i + 1
129 128 dmeqd φ i 0 ..^ M dom F Q i Q i + 1 = dom F int topGen ran . Q i Q i + 1
130 ioontr int topGen ran . Q i Q i + 1 = Q i Q i + 1
131 130 reseq2i F int topGen ran . Q i Q i + 1 = F Q i Q i + 1
132 131 dmeqi dom F int topGen ran . Q i Q i + 1 = dom F Q i Q i + 1
133 132 a1i φ i 0 ..^ M dom F int topGen ran . Q i Q i + 1 = dom F Q i Q i + 1
134 cncff F Q i Q i + 1 : Q i Q i + 1 cn F Q i Q i + 1 : Q i Q i + 1
135 fdm F Q i Q i + 1 : Q i Q i + 1 dom F Q i Q i + 1 = Q i Q i + 1
136 10 134 135 3syl φ i 0 ..^ M dom F Q i Q i + 1 = Q i Q i + 1
137 129 133 136 3eqtrd φ i 0 ..^ M dom F Q i Q i + 1 = Q i Q i + 1
138 dvcn F Q i Q i + 1 : Q i Q i + 1 Q i Q i + 1 dom F Q i Q i + 1 = Q i Q i + 1 F Q i Q i + 1 : Q i Q i + 1 cn
139 114 120 121 137 138 syl31anc φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1 cn
140 121 114 sstrd φ i 0 ..^ M Q i Q i + 1
141 84 adantr φ i 0 ..^ M Q : 0 M
142 fzofzp1 i 0 ..^ M i + 1 0 M
143 142 adantl φ i 0 ..^ M i + 1 0 M
144 141 143 ffvelcdmd φ i 0 ..^ M Q i + 1
145 144 rexrd φ i 0 ..^ M Q i + 1 *
146 elfzofz i 0 ..^ M i 0 M
147 146 adantl φ i 0 ..^ M i 0 M
148 141 147 ffvelcdmd φ i 0 ..^ M Q i
149 81 simprrd φ i 0 ..^ M Q i < Q i + 1
150 149 r19.21bi φ i 0 ..^ M Q i < Q i + 1
151 125 145 148 150 lptioo1cn φ i 0 ..^ M Q i limPt TopOpen fld Q i Q i + 1
152 117 adantr φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1
153 ssidd φ
154 118 122 153 dvbss φ dom F
155 dvfre F : F : dom F
156 1 153 155 syl2anc φ F : dom F
157 0re 0
158 68 157 67 lttri π < 0 0 < π π < π
159 71 73 158 mp2an π < π
160 159 a1i φ π < π
161 90 simplld φ Q 0 = π
162 10 134 syl φ i 0 ..^ M F Q i Q i + 1 : Q i Q i + 1
163 162 140 151 11 125 ellimciota φ i 0 ..^ M ι x | x F Q i Q i + 1 lim Q i F Q i Q i + 1 lim Q i
164 148 rexrd φ i 0 ..^ M Q i *
165 125 164 144 150 lptioo2cn φ i 0 ..^ M Q i + 1 limPt TopOpen fld Q i Q i + 1
166 162 140 165 12 125 ellimciota φ i 0 ..^ M ι x | x F Q i Q i + 1 lim Q i + 1 F Q i Q i + 1 lim Q i + 1
167 122 adantr φ k F :
168 zre k k
169 168 adantl φ k k
170 2pire 2 π
171 170 a1i φ 2 π
172 2 171 eqeltrid φ T
173 172 adantr φ k T
174 169 173 remulcld φ k k T
175 167 adantr φ k t F :
176 173 adantr φ k t T
177 simplr φ k t k
178 simpr φ k t t
179 3 ad4ant14 φ k t x F x + T = F x
180 175 176 177 178 179 fperiodmul φ k t F t + k T = F t
181 eqid D F = D F
182 167 174 180 181 fperdvper φ k t dom F t + k T dom F F t + k T = F t
183 182 an32s φ t dom F k t + k T dom F F t + k T = F t
184 183 simpld φ t dom F k t + k T dom F
185 183 simprd φ t dom F k F t + k T = F t
186 fveq2 j = i Q j = Q i
187 fvoveq1 j = i Q j + 1 = Q i + 1
188 186 187 oveq12d j = i Q j Q j + 1 = Q i Q i + 1
189 188 cbvmptv j 0 ..^ M Q j Q j + 1 = i 0 ..^ M Q i Q i + 1
190 eqid t t + π t T T = t t + π t T T
191 154 156 69 70 160 78 8 84 161 91 10 163 166 184 185 189 190 fourierdlem71 φ z t dom F F t z
192 191 adantr φ i 0 ..^ M z t dom F F t z
193 nfv t φ i 0 ..^ M
194 nfra1 t t dom F F t z
195 193 194 nfan t φ i 0 ..^ M t dom F F t z
196 128 131 eqtrdi φ i 0 ..^ M D F Q i Q i + 1 = F Q i Q i + 1
197 196 fveq1d φ i 0 ..^ M F Q i Q i + 1 t = F Q i Q i + 1 t
198 fvres t Q i Q i + 1 F Q i Q i + 1 t = F t
199 197 198 sylan9eq φ i 0 ..^ M t Q i Q i + 1 F Q i Q i + 1 t = F t
200 199 fveq2d φ i 0 ..^ M t Q i Q i + 1 F Q i Q i + 1 t = F t
201 200 adantlr φ i 0 ..^ M t dom F F t z t Q i Q i + 1 F Q i Q i + 1 t = F t
202 simplr φ i 0 ..^ M t dom F F t z t Q i Q i + 1 t dom F F t z
203 ssdmres Q i Q i + 1 dom F dom F Q i Q i + 1 = Q i Q i + 1
204 136 203 sylibr φ i 0 ..^ M Q i Q i + 1 dom F
205 204 ad2antrr φ i 0 ..^ M t dom F F t z t Q i Q i + 1 Q i Q i + 1 dom F
206 simpr φ i 0 ..^ M t dom F F t z t Q i Q i + 1 t Q i Q i + 1
207 205 206 sseldd φ i 0 ..^ M t dom F F t z t Q i Q i + 1 t dom F
208 rspa t dom F F t z t dom F F t z
209 202 207 208 syl2anc φ i 0 ..^ M t dom F F t z t Q i Q i + 1 F t z
210 201 209 eqbrtrd φ i 0 ..^ M t dom F F t z t Q i Q i + 1 F Q i Q i + 1 t z
211 195 210 ralrimia φ i 0 ..^ M t dom F F t z t Q i Q i + 1 F Q i Q i + 1 t z
212 211 ex φ i 0 ..^ M t dom F F t z t Q i Q i + 1 F Q i Q i + 1 t z
213 212 reximdv φ i 0 ..^ M z t dom F F t z z t Q i Q i + 1 F Q i Q i + 1 t z
214 192 213 mpd φ i 0 ..^ M z t Q i Q i + 1 F Q i Q i + 1 t z
215 148 144 152 137 214 ioodvbdlimc1 φ i 0 ..^ M F Q i Q i + 1 lim Q i
216 120 140 151 215 125 ellimciota φ i 0 ..^ M ι y | y F Q i Q i + 1 lim Q i F Q i Q i + 1 lim Q i
217 148 144 152 137 214 ioodvbdlimc2 φ i 0 ..^ M F Q i Q i + 1 lim Q i + 1
218 120 140 165 217 125 ellimciota φ i 0 ..^ M ι y | y F Q i Q i + 1 lim Q i + 1 F Q i Q i + 1 lim Q i + 1
219 resindm F −∞ X dom F = F −∞ X
220 219 a1i φ F −∞ X dom F = F −∞ X
221 inss2 −∞ X dom F dom F
222 221 a1i φ −∞ X dom F dom F
223 156 222 fssresd φ F −∞ X dom F : −∞ X dom F
224 220 223 feq1dd φ F −∞ X : −∞ X dom F
225 224 118 fssd φ F −∞ X : −∞ X dom F
226 ioosscn −∞ X
227 ssinss1 −∞ X −∞ X dom F
228 226 227 ax-mp −∞ X dom F
229 228 a1i φ −∞ X dom F
230 3simpb φ x dom F k φ k
231 simp2 φ x dom F k x dom F
232 167 adantr φ k x F :
233 173 adantr φ k x T
234 simplr φ k x k
235 simpr φ k x x
236 eleq1w x = y x y
237 236 anbi2d x = y φ x φ y
238 fvoveq1 x = y F x + T = F y + T
239 fveq2 x = y F x = F y
240 238 239 eqeq12d x = y F x + T = F x F y + T = F y
241 237 240 imbi12d x = y φ x F x + T = F x φ y F y + T = F y
242 241 3 chvarvv φ y F y + T = F y
243 242 ad4ant14 φ k x y F y + T = F y
244 232 233 234 235 243 fperiodmul φ k x F x + k T = F x
245 167 174 244 181 fperdvper φ k x dom F x + k T dom F F x + k T = F x
246 230 231 245 syl2anc φ x dom F k x + k T dom F F x + k T = F x
247 246 simpld φ x dom F k x + k T dom F
248 oveq2 w = x π w = π x
249 248 fvoveq1d w = x π w T = π x T
250 249 oveq1d w = x π w T T = π x T T
251 250 cbvmptv w π w T T = x π x T T
252 eqid x x + w π w T T x = x x + w π w T T x
253 69 70 160 78 247 4 251 252 7 8 9 204 fourierdlem41 φ y y < X y X dom F y X < y X y dom F
254 253 simpld φ y y < X y X dom F
255 125 cnfldtop TopOpen fld Top
256 mnfxr −∞ *
257 rexr y y *
258 257 mnfled y −∞ y
259 iooss1 −∞ * −∞ y y X −∞ X
260 256 258 259 sylancr y y X −∞ X
261 260 3ad2ant2 φ y y X dom F y X −∞ X
262 simp3 φ y y X dom F y X dom F
263 261 262 ssind φ y y X dom F y X −∞ X dom F
264 unicntop = TopOpen fld
265 264 lpss3 TopOpen fld Top −∞ X dom F y X −∞ X dom F limPt TopOpen fld y X limPt TopOpen fld −∞ X dom F
266 255 228 263 265 mp3an12i φ y y X dom F limPt TopOpen fld y X limPt TopOpen fld −∞ X dom F
267 266 3adant3l φ y y < X y X dom F limPt TopOpen fld y X limPt TopOpen fld −∞ X dom F
268 257 3ad2ant2 φ y y < X y X dom F y *
269 4 3ad2ant1 φ y y < X y X dom F X
270 simp3l φ y y < X y X dom F y < X
271 125 268 269 270 lptioo2cn φ y y < X y X dom F X limPt TopOpen fld y X
272 267 271 sseldd φ y y < X y X dom F X limPt TopOpen fld −∞ X dom F
273 272 rexlimdv3a φ y y < X y X dom F X limPt TopOpen fld −∞ X dom F
274 254 273 mpd φ X limPt TopOpen fld −∞ X dom F
275 246 simprd φ x dom F k F x + k T = F x
276 oveq2 y = x π y = π x
277 276 fvoveq1d y = x π y T = π x T
278 277 oveq1d y = x π y T T = π x T T
279 278 cbvmptv y π y T T = x π x T T
280 id z = x z = x
281 fveq2 z = x y π y T T z = y π y T T x
282 280 281 oveq12d z = x z + y π y T T z = x + y π y T T x
283 282 cbvmptv z z + y π y T T z = x x + y π y T T x
284 69 70 160 7 78 8 9 154 156 247 275 10 166 4 279 283 fourierdlem49 φ F −∞ X lim X
285 225 229 274 284 125 ellimciota φ ι x | x F −∞ X lim X F −∞ X lim X
286 resindm F X +∞ dom F = F X +∞
287 286 a1i φ F X +∞ dom F = F X +∞
288 inss2 X +∞ dom F dom F
289 288 a1i φ X +∞ dom F dom F
290 156 289 fssresd φ F X +∞ dom F : X +∞ dom F
291 287 290 feq1dd φ F X +∞ : X +∞ dom F
292 291 118 fssd φ F X +∞ : X +∞ dom F
293 ioosscn X +∞
294 ssinss1 X +∞ X +∞ dom F
295 293 294 ax-mp X +∞ dom F
296 295 a1i φ X +∞ dom F
297 253 simprd φ y X < y X y dom F
298 pnfxr +∞ *
299 257 pnfged y y +∞
300 iooss2 +∞ * y +∞ X y X +∞
301 298 299 300 sylancr y X y X +∞
302 301 3ad2ant2 φ y X y dom F X y X +∞
303 simp3 φ y X y dom F X y dom F
304 302 303 ssind φ y X y dom F X y X +∞ dom F
305 264 lpss3 TopOpen fld Top X +∞ dom F X y X +∞ dom F limPt TopOpen fld X y limPt TopOpen fld X +∞ dom F
306 255 295 304 305 mp3an12i φ y X y dom F limPt TopOpen fld X y limPt TopOpen fld X +∞ dom F
307 306 3adant3l φ y X < y X y dom F limPt TopOpen fld X y limPt TopOpen fld X +∞ dom F
308 257 3ad2ant2 φ y X < y X y dom F y *
309 4 3ad2ant1 φ y X < y X y dom F X
310 simp3l φ y X < y X y dom F X < y
311 125 308 309 310 lptioo1cn φ y X < y X y dom F X limPt TopOpen fld X y
312 307 311 sseldd φ y X < y X y dom F X limPt TopOpen fld X +∞ dom F
313 312 rexlimdv3a φ y X < y X y dom F X limPt TopOpen fld X +∞ dom F
314 297 313 mpd φ X limPt TopOpen fld X +∞ dom F
315 biid φ i 0 ..^ M w Q i Q i + 1 k w = X + k T φ i 0 ..^ M w Q i Q i + 1 k w = X + k T
316 69 70 160 7 78 8 9 156 247 275 10 163 4 279 283 315 fourierdlem48 φ F X +∞ lim X
317 292 296 314 316 125 ellimciota φ ι x | x F X +∞ lim X F X +∞ lim X
318 fveq2 n = k A n = A k
319 fvoveq1 n = k cos n X = cos k X
320 318 319 oveq12d n = k A n cos n X = A k cos k X
321 fveq2 n = k B n = B k
322 fvoveq1 n = k sin n X = sin k X
323 321 322 oveq12d n = k B n sin n X = B k sin k X
324 320 323 oveq12d n = k A n cos n X + B n sin n X = A k cos k X + B k sin k X
325 324 cbvsumv n = 1 m A n cos n X + B n sin n X = k = 1 m A k cos k X + B k sin k X
326 oveq2 j = m 1 j = 1 m
327 326 eqcomd j = m 1 m = 1 j
328 327 sumeq1d j = m k = 1 m A k cos k X + B k sin k X = k = 1 j A k cos k X + B k sin k X
329 325 328 eqtr2id j = m k = 1 j A k cos k X + B k sin k X = n = 1 m A n cos n X + B n sin n X
330 329 oveq2d j = m A 0 2 + k = 1 j A k cos k X + B k sin k X = A 0 2 + n = 1 m A n cos n X + B n sin n X
331 330 cbvmptv j A 0 2 + k = 1 j A k cos k X + B k sin k X = m A 0 2 + n = 1 m A n cos n X + B n sin n X
332 1 fdmd φ dom F =
333 332 eqimssd φ dom F
334 1 ffdmd φ F : dom F
335 333 sselda φ t dom F t
336 335 adantr φ t dom F k t
337 168 adantl φ t dom F k k
338 173 adantlr φ t dom F k T
339 337 338 remulcld φ t dom F k k T
340 336 339 readdcld φ t dom F k t + k T
341 332 eqcomd φ = dom F
342 341 ad2antrr φ t dom F k = dom F
343 340 342 eleqtrd φ t dom F k t + k T dom F
344 id φ k φ k
345 344 adantlr φ t dom F k φ k
346 345 336 180 syl2anc φ t dom F k F t + k T = F t
347 333 334 69 70 160 78 8 84 161 91 139 216 218 343 346 189 190 fourierdlem71 φ u t dom F F t u
348 332 raleqdv φ t dom F F t u t F t u
349 348 rexbidv φ u t dom F F t u u t F t u
350 347 349 mpbid φ u t F t u
351 1 36 7 8 9 43 66 4 112 2 3 139 216 218 10 285 317 5 6 13 14 331 15 350 191 4 fourierdlem112 φ seq 1 + S L + R 2 A 0 2 A 0 2 + n A n cos n X + B n sin n X = L + R 2