Metamath Proof Explorer


Theorem dvnxpaek

Description: The n -th derivative of the polynomial ( x + A ) ^ K . (Contributed by Glauco Siliprandi, 5-Apr-2020)

Ref Expression
Hypotheses dvnxpaek.s φ S
dvnxpaek.x φ X TopOpen fld 𝑡 S
dvnxpaek.a φ A
dvnxpaek.k φ K 0
dvnxpaek.f F = x X x + A K
Assertion dvnxpaek φ N 0 S D n F N = x X if K < N 0 K ! K N ! x + A K N

Proof

Step Hyp Ref Expression
1 dvnxpaek.s φ S
2 dvnxpaek.x φ X TopOpen fld 𝑡 S
3 dvnxpaek.a φ A
4 dvnxpaek.k φ K 0
5 dvnxpaek.f F = x X x + A K
6 fveq2 n = 0 S D n F n = S D n F 0
7 breq2 n = 0 K < n K < 0
8 eqidd n = 0 0 = 0
9 oveq2 n = 0 K n = K 0
10 9 fveq2d n = 0 K n ! = K 0 !
11 10 oveq2d n = 0 K ! K n ! = K ! K 0 !
12 9 oveq2d n = 0 x + A K n = x + A K 0
13 11 12 oveq12d n = 0 K ! K n ! x + A K n = K ! K 0 ! x + A K 0
14 7 8 13 ifbieq12d n = 0 if K < n 0 K ! K n ! x + A K n = if K < 0 0 K ! K 0 ! x + A K 0
15 14 mpteq2dv n = 0 x X if K < n 0 K ! K n ! x + A K n = x X if K < 0 0 K ! K 0 ! x + A K 0
16 6 15 eqeq12d n = 0 S D n F n = x X if K < n 0 K ! K n ! x + A K n S D n F 0 = x X if K < 0 0 K ! K 0 ! x + A K 0
17 fveq2 n = m S D n F n = S D n F m
18 breq2 n = m K < n K < m
19 eqidd n = m 0 = 0
20 oveq2 n = m K n = K m
21 20 fveq2d n = m K n ! = K m !
22 21 oveq2d n = m K ! K n ! = K ! K m !
23 20 oveq2d n = m x + A K n = x + A K m
24 22 23 oveq12d n = m K ! K n ! x + A K n = K ! K m ! x + A K m
25 18 19 24 ifbieq12d n = m if K < n 0 K ! K n ! x + A K n = if K < m 0 K ! K m ! x + A K m
26 25 mpteq2dv n = m x X if K < n 0 K ! K n ! x + A K n = x X if K < m 0 K ! K m ! x + A K m
27 17 26 eqeq12d n = m S D n F n = x X if K < n 0 K ! K n ! x + A K n S D n F m = x X if K < m 0 K ! K m ! x + A K m
28 fveq2 n = m + 1 S D n F n = S D n F m + 1
29 breq2 n = m + 1 K < n K < m + 1
30 eqidd n = m + 1 0 = 0
31 oveq2 n = m + 1 K n = K m + 1
32 31 fveq2d n = m + 1 K n ! = K m + 1 !
33 32 oveq2d n = m + 1 K ! K n ! = K ! K m + 1 !
34 31 oveq2d n = m + 1 x + A K n = x + A K m + 1
35 33 34 oveq12d n = m + 1 K ! K n ! x + A K n = K ! K m + 1 ! x + A K m + 1
36 29 30 35 ifbieq12d n = m + 1 if K < n 0 K ! K n ! x + A K n = if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
37 36 mpteq2dv n = m + 1 x X if K < n 0 K ! K n ! x + A K n = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
38 28 37 eqeq12d n = m + 1 S D n F n = x X if K < n 0 K ! K n ! x + A K n S D n F m + 1 = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
39 fveq2 n = N S D n F n = S D n F N
40 breq2 n = N K < n K < N
41 eqidd n = N 0 = 0
42 oveq2 n = N K n = K N
43 42 fveq2d n = N K n ! = K N !
44 43 oveq2d n = N K ! K n ! = K ! K N !
45 42 oveq2d n = N x + A K n = x + A K N
46 44 45 oveq12d n = N K ! K n ! x + A K n = K ! K N ! x + A K N
47 40 41 46 ifbieq12d n = N if K < n 0 K ! K n ! x + A K n = if K < N 0 K ! K N ! x + A K N
48 47 mpteq2dv n = N x X if K < n 0 K ! K n ! x + A K n = x X if K < N 0 K ! K N ! x + A K N
49 39 48 eqeq12d n = N S D n F n = x X if K < n 0 K ! K n ! x + A K n S D n F N = x X if K < N 0 K ! K N ! x + A K N
50 recnprss S S
51 1 50 syl φ S
52 cnex V
53 52 a1i φ V
54 restsspw TopOpen fld 𝑡 S 𝒫 S
55 id X TopOpen fld 𝑡 S X TopOpen fld 𝑡 S
56 54 55 sselid X TopOpen fld 𝑡 S X 𝒫 S
57 elpwi X 𝒫 S X S
58 56 57 syl X TopOpen fld 𝑡 S X S
59 2 58 syl φ X S
60 59 51 sstrd φ X
61 60 adantr φ x X X
62 simpr φ x X x X
63 61 62 sseldd φ x X x
64 3 adantr φ x X A
65 63 64 addcld φ x X x + A
66 4 adantr φ x X K 0
67 65 66 expcld φ x X x + A K
68 67 5 fmptd φ F : X
69 elpm2r V S F : X X S F 𝑝𝑚 S
70 53 1 68 59 69 syl22anc φ F 𝑝𝑚 S
71 dvn0 S F 𝑝𝑚 S S D n F 0 = F
72 51 70 71 syl2anc φ S D n F 0 = F
73 5 a1i φ F = x X x + A K
74 4 nn0ge0d φ 0 K
75 0red φ 0
76 4 nn0red φ K
77 75 76 lenltd φ 0 K ¬ K < 0
78 74 77 mpbid φ ¬ K < 0
79 78 iffalsed φ if K < 0 0 K ! K 0 ! x + A K 0 = K ! K 0 ! x + A K 0
80 79 adantr φ x X if K < 0 0 K ! K 0 ! x + A K 0 = K ! K 0 ! x + A K 0
81 4 nn0cnd φ K
82 81 subid1d φ K 0 = K
83 82 fveq2d φ K 0 ! = K !
84 83 oveq2d φ K ! K 0 ! = K ! K !
85 faccl K 0 K !
86 4 85 syl φ K !
87 86 nncnd φ K !
88 86 nnne0d φ K ! 0
89 87 88 dividd φ K ! K ! = 1
90 84 89 eqtrd φ K ! K 0 ! = 1
91 82 oveq2d φ x + A K 0 = x + A K
92 90 91 oveq12d φ K ! K 0 ! x + A K 0 = 1 x + A K
93 92 adantr φ x X K ! K 0 ! x + A K 0 = 1 x + A K
94 67 mulid2d φ x X 1 x + A K = x + A K
95 80 93 94 3eqtrrd φ x X x + A K = if K < 0 0 K ! K 0 ! x + A K 0
96 95 mpteq2dva φ x X x + A K = x X if K < 0 0 K ! K 0 ! x + A K 0
97 72 73 96 3eqtrd φ S D n F 0 = x X if K < 0 0 K ! K 0 ! x + A K 0
98 51 adantr φ m 0 S
99 70 adantr φ m 0 F 𝑝𝑚 S
100 simpr φ m 0 m 0
101 dvnp1 S F 𝑝𝑚 S m 0 S D n F m + 1 = S D S D n F m
102 98 99 100 101 syl3anc φ m 0 S D n F m + 1 = S D S D n F m
103 102 adantr φ m 0 S D n F m = x X if K < m 0 K ! K m ! x + A K m S D n F m + 1 = S D S D n F m
104 oveq2 S D n F m = x X if K < m 0 K ! K m ! x + A K m S D S D n F m = dx X if K < m 0 K ! K m ! x + A K m dS x
105 104 adantl φ m 0 S D n F m = x X if K < m 0 K ! K m ! x + A K m S D S D n F m = dx X if K < m 0 K ! K m ! x + A K m dS x
106 iftrue K < m if K < m 0 K ! K m ! x + A K m = 0
107 106 mpteq2dv K < m x X if K < m 0 K ! K m ! x + A K m = x X 0
108 107 oveq2d K < m dx X if K < m 0 K ! K m ! x + A K m dS x = dx X 0 dS x
109 108 adantl φ m 0 K < m dx X if K < m 0 K ! K m ! x + A K m dS x = dx X 0 dS x
110 0cnd φ 0
111 1 2 110 dvmptconst φ dx X 0 dS x = x X 0
112 111 ad2antrr φ m 0 K < m dx X 0 dS x = x X 0
113 76 ad2antrr φ m 0 K < m K
114 nn0re m 0 m
115 114 ad2antlr φ m 0 K < m m
116 simpr φ m 0 K < m K < m
117 113 115 116 ltled φ m 0 K < m K m
118 4 nn0zd φ K
119 118 adantr φ m 0 K
120 100 nn0zd φ m 0 m
121 zleltp1 K m K m K < m + 1
122 119 120 121 syl2anc φ m 0 K m K < m + 1
123 122 adantr φ m 0 K < m K m K < m + 1
124 117 123 mpbid φ m 0 K < m K < m + 1
125 124 iftrued φ m 0 K < m if K < m + 1 0 K ! K m + 1 ! x + A K m + 1 = 0
126 125 mpteq2dv φ m 0 K < m x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1 = x X 0
127 126 eqcomd φ m 0 K < m x X 0 = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
128 109 112 127 3eqtrd φ m 0 K < m dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
129 simpl φ m 0 ¬ K < m φ m 0
130 simpr φ m 0 ¬ K < m ¬ K < m
131 129 100 114 3syl φ m 0 ¬ K < m m
132 76 ad2antrr φ m 0 ¬ K < m K
133 131 132 lenltd φ m 0 ¬ K < m m K ¬ K < m
134 130 133 mpbird φ m 0 ¬ K < m m K
135 simpr φ m 0 m = K m = K
136 114 ad2antlr φ m 0 m = K m
137 76 ad2antrr φ m 0 m = K K
138 136 137 lttri3d φ m 0 m = K m = K ¬ m < K ¬ K < m
139 135 138 mpbid φ m 0 m = K ¬ m < K ¬ K < m
140 simpr ¬ m < K ¬ K < m ¬ K < m
141 139 140 syl φ m 0 m = K ¬ K < m
142 141 iffalsed φ m 0 m = K if K < m 0 K ! K m ! x + A K m = K ! K m ! x + A K m
143 142 mpteq2dv φ m 0 m = K x X if K < m 0 K ! K m ! x + A K m = x X K ! K m ! x + A K m
144 143 oveq2d φ m 0 m = K dx X if K < m 0 K ! K m ! x + A K m dS x = dx X K ! K m ! x + A K m dS x
145 oveq2 m = K K m = K K
146 145 fveq2d m = K K m ! = K K !
147 146 adantl φ m = K K m ! = K K !
148 81 subidd φ K K = 0
149 148 fveq2d φ K K ! = 0 !
150 fac0 0 ! = 1
151 150 a1i φ 0 ! = 1
152 149 151 eqtrd φ K K ! = 1
153 152 adantr φ m = K K K ! = 1
154 147 153 eqtrd φ m = K K m ! = 1
155 154 oveq2d φ m = K K ! K m ! = K ! 1
156 87 div1d φ K ! 1 = K !
157 156 adantr φ m = K K ! 1 = K !
158 155 157 eqtrd φ m = K K ! K m ! = K !
159 158 adantr φ m = K x X K ! K m ! = K !
160 145 adantl φ m = K K m = K K
161 148 adantr φ m = K K K = 0
162 160 161 eqtrd φ m = K K m = 0
163 162 oveq2d φ m = K x + A K m = x + A 0
164 163 adantr φ m = K x X x + A K m = x + A 0
165 65 exp0d φ x X x + A 0 = 1
166 165 adantlr φ m = K x X x + A 0 = 1
167 164 166 eqtrd φ m = K x X x + A K m = 1
168 159 167 oveq12d φ m = K x X K ! K m ! x + A K m = K ! 1
169 87 mulid1d φ K ! 1 = K !
170 169 ad2antrr φ m = K x X K ! 1 = K !
171 168 170 eqtrd φ m = K x X K ! K m ! x + A K m = K !
172 171 mpteq2dva φ m = K x X K ! K m ! x + A K m = x X K !
173 172 oveq2d φ m = K dx X K ! K m ! x + A K m dS x = dx X K ! dS x
174 1 2 87 dvmptconst φ dx X K ! dS x = x X 0
175 174 adantr φ m = K dx X K ! dS x = x X 0
176 173 175 eqtrd φ m = K dx X K ! K m ! x + A K m dS x = x X 0
177 176 adantlr φ m 0 m = K dx X K ! K m ! x + A K m dS x = x X 0
178 137 ltp1d φ m 0 m = K K < K + 1
179 oveq1 m = K m + 1 = K + 1
180 179 eqcomd m = K K + 1 = m + 1
181 180 adantl φ m 0 m = K K + 1 = m + 1
182 178 181 breqtrd φ m 0 m = K K < m + 1
183 182 iftrued φ m 0 m = K if K < m + 1 0 K ! K m + 1 ! x + A K m + 1 = 0
184 183 eqcomd φ m 0 m = K 0 = if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
185 184 mpteq2dv φ m 0 m = K x X 0 = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
186 144 177 185 3eqtrd φ m 0 m = K dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
187 186 adantlr φ m 0 m K m = K dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
188 simpll φ m 0 m K ¬ m = K φ m 0
189 188 100 114 3syl φ m 0 m K ¬ m = K m
190 76 ad3antrrr φ m 0 m K ¬ m = K K
191 simplr φ m 0 m K ¬ m = K m K
192 neqne ¬ m = K m K
193 192 necomd ¬ m = K K m
194 193 adantl φ m 0 m K ¬ m = K K m
195 189 190 191 194 leneltd φ m 0 m K ¬ m = K m < K
196 114 ad2antlr φ m 0 m < K m
197 76 ad2antrr φ m 0 m < K K
198 simpr φ m 0 m < K m < K
199 196 197 198 ltled φ m 0 m < K m K
200 196 197 lenltd φ m 0 m < K m K ¬ K < m
201 199 200 mpbid φ m 0 m < K ¬ K < m
202 201 iffalsed φ m 0 m < K if K < m 0 K ! K m ! x + A K m = K ! K m ! x + A K m
203 202 mpteq2dv φ m 0 m < K x X if K < m 0 K ! K m ! x + A K m = x X K ! K m ! x + A K m
204 203 oveq2d φ m 0 m < K dx X if K < m 0 K ! K m ! x + A K m dS x = dx X K ! K m ! x + A K m dS x
205 1 adantr φ m 0 S
206 205 adantr φ m 0 m < K S
207 87 ad2antrr φ m 0 m < K K !
208 100 adantr φ m 0 m < K m 0
209 4 ad2antrr φ m 0 m < K K 0
210 nn0sub m 0 K 0 m K K m 0
211 208 209 210 syl2anc φ m 0 m < K m K K m 0
212 199 211 mpbid φ m 0 m < K K m 0
213 faccl K m 0 K m !
214 212 213 syl φ m 0 m < K K m !
215 214 nncnd φ m 0 m < K K m !
216 214 nnne0d φ m 0 m < K K m ! 0
217 207 215 216 divcld φ m 0 m < K K ! K m !
218 217 adantr φ m 0 m < K x X K ! K m !
219 75 ad3antrrr φ m 0 m < K x X 0
220 2 adantr φ m 0 X TopOpen fld 𝑡 S
221 220 adantr φ m 0 m < K X TopOpen fld 𝑡 S
222 206 221 217 dvmptconst φ m 0 m < K dx X K ! K m ! dS x = x X 0
223 65 adantlr φ m 0 x X x + A
224 223 adantlr φ m 0 m < K x X x + A
225 212 adantr φ m 0 m < K x X K m 0
226 224 225 expcld φ m 0 m < K x X x + A K m
227 225 nn0cnd φ m 0 m < K x X K m
228 212 nn0zd φ m 0 m < K K m
229 196 197 posdifd φ m 0 m < K m < K 0 < K m
230 198 229 mpbid φ m 0 m < K 0 < K m
231 228 230 jca φ m 0 m < K K m 0 < K m
232 elnnz K m K m 0 < K m
233 231 232 sylibr φ m 0 m < K K m
234 nnm1nn0 K m K - m - 1 0
235 233 234 syl φ m 0 m < K K - m - 1 0
236 235 adantr φ m 0 m < K x X K - m - 1 0
237 224 236 expcld φ m 0 m < K x X x + A K - m - 1
238 227 237 mulcld φ m 0 m < K x X K m x + A K - m - 1
239 3 ad2antrr φ m 0 m < K A
240 206 221 239 233 dvxpaek φ m 0 m < K dx X x + A K m dS x = x X K m x + A K - m - 1
241 206 218 219 222 226 238 240 dvmptmul φ m 0 m < K dx X K ! K m ! x + A K m dS x = x X 0 x + A K m + K m x + A K - m - 1 K ! K m !
242 226 mul02d φ m 0 m < K x X 0 x + A K m = 0
243 242 oveq1d φ m 0 m < K x X 0 x + A K m + K m x + A K - m - 1 K ! K m ! = 0 + K m x + A K - m - 1 K ! K m !
244 238 218 mulcld φ m 0 m < K x X K m x + A K - m - 1 K ! K m !
245 244 addid2d φ m 0 m < K x X 0 + K m x + A K - m - 1 K ! K m ! = K m x + A K - m - 1 K ! K m !
246 120 adantr φ m 0 m < K m
247 119 adantr φ m 0 m < K K
248 zltp1le m K m < K m + 1 K
249 246 247 248 syl2anc φ m 0 m < K m < K m + 1 K
250 198 249 mpbid φ m 0 m < K m + 1 K
251 peano2re m m + 1
252 196 251 syl φ m 0 m < K m + 1
253 252 197 lenltd φ m 0 m < K m + 1 K ¬ K < m + 1
254 250 253 mpbid φ m 0 m < K ¬ K < m + 1
255 254 adantr φ m 0 m < K x X ¬ K < m + 1
256 255 iffalsed φ m 0 m < K x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1 = K ! K m + 1 ! x + A K m + 1
257 218 227 237 mulassd φ m 0 m < K x X K ! K m ! K m x + A K - m - 1 = K ! K m ! K m x + A K - m - 1
258 257 eqcomd φ m 0 m < K x X K ! K m ! K m x + A K - m - 1 = K ! K m ! K m x + A K - m - 1
259 233 nncnd φ m 0 m < K K m
260 207 215 259 216 div32d φ m 0 m < K K ! K m ! K m = K ! K m K m !
261 facnn2 K m K m ! = K - m - 1 ! K m
262 233 261 syl φ m 0 m < K K m ! = K - m - 1 ! K m
263 262 oveq2d φ m 0 m < K K m K m ! = K m K - m - 1 ! K m
264 faccl K - m - 1 0 K - m - 1 !
265 234 264 syl K m K - m - 1 !
266 265 nncnd K m K - m - 1 !
267 233 266 syl φ m 0 m < K K - m - 1 !
268 235 264 syl φ m 0 m < K K - m - 1 !
269 nnne0 K - m - 1 ! K - m - 1 ! 0
270 268 269 syl φ m 0 m < K K - m - 1 ! 0
271 nnne0 K m K m 0
272 233 271 syl φ m 0 m < K K m 0
273 267 259 270 272 divcan8d φ m 0 m < K K m K - m - 1 ! K m = 1 K - m - 1 !
274 263 273 eqtrd φ m 0 m < K K m K m ! = 1 K - m - 1 !
275 274 oveq2d φ m 0 m < K K ! K m K m ! = K ! 1 K - m - 1 !
276 eqidd φ m 0 m < K K ! 1 K - m - 1 ! = K ! 1 K - m - 1 !
277 260 275 276 3eqtrd φ m 0 m < K K ! K m ! K m = K ! 1 K - m - 1 !
278 277 adantr φ m 0 m < K x X K ! K m ! K m = K ! 1 K - m - 1 !
279 81 adantr φ m 0 K
280 100 nn0cnd φ m 0 m
281 1cnd φ m 0 1
282 279 280 281 subsub4d φ m 0 K - m - 1 = K m + 1
283 282 oveq2d φ m 0 x + A K - m - 1 = x + A K m + 1
284 283 ad2antrr φ m 0 m < K x X x + A K - m - 1 = x + A K m + 1
285 278 284 oveq12d φ m 0 m < K x X K ! K m ! K m x + A K - m - 1 = K ! 1 K - m - 1 ! x + A K m + 1
286 282 adantr φ m 0 m < K K - m - 1 = K m + 1
287 286 eqcomd φ m 0 m < K K m + 1 = K - m - 1
288 287 fveq2d φ m 0 m < K K m + 1 ! = K - m - 1 !
289 288 oveq2d φ m 0 m < K K ! K m + 1 ! = K ! K - m - 1 !
290 207 267 270 divrecd φ m 0 m < K K ! K - m - 1 ! = K ! 1 K - m - 1 !
291 289 290 eqtr2d φ m 0 m < K K ! 1 K - m - 1 ! = K ! K m + 1 !
292 291 adantr φ m 0 m < K x X K ! 1 K - m - 1 ! = K ! K m + 1 !
293 292 oveq1d φ m 0 m < K x X K ! 1 K - m - 1 ! x + A K m + 1 = K ! K m + 1 ! x + A K m + 1
294 258 285 293 3eqtrrd φ m 0 m < K x X K ! K m + 1 ! x + A K m + 1 = K ! K m ! K m x + A K - m - 1
295 218 238 mulcomd φ m 0 m < K x X K ! K m ! K m x + A K - m - 1 = K m x + A K - m - 1 K ! K m !
296 256 294 295 3eqtrrd φ m 0 m < K x X K m x + A K - m - 1 K ! K m ! = if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
297 243 245 296 3eqtrd φ m 0 m < K x X 0 x + A K m + K m x + A K - m - 1 K ! K m ! = if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
298 297 mpteq2dva φ m 0 m < K x X 0 x + A K m + K m x + A K - m - 1 K ! K m ! = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
299 204 241 298 3eqtrd φ m 0 m < K dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
300 188 195 299 syl2anc φ m 0 m K ¬ m = K dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
301 187 300 pm2.61dan φ m 0 m K dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
302 129 134 301 syl2anc φ m 0 ¬ K < m dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
303 128 302 pm2.61dan φ m 0 dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
304 303 adantr φ m 0 S D n F m = x X if K < m 0 K ! K m ! x + A K m dx X if K < m 0 K ! K m ! x + A K m dS x = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
305 103 105 304 3eqtrd φ m 0 S D n F m = x X if K < m 0 K ! K m ! x + A K m S D n F m + 1 = x X if K < m + 1 0 K ! K m + 1 ! x + A K m + 1
306 16 27 38 49 97 305 nn0indd φ N 0 S D n F N = x X if K < N 0 K ! K N ! x + A K N