Knowledge

Talk:Removable singularity

Source 📝

84: 74: 53: 22: 165:
a) It is defined as the limit at a of the function existing (i.e. the limit is the same as you approach from all sides, but the function is defined as something else when it is actually at a. (sorry I don't feel like inserting the latex right now).
215:
The proof given here strikes me as rather strange. In particular, it's necessary to show that the Taylor series won't have a first order term. And what is the motivation for multiplying by (z-a)^2 rather than by (z-a)? Ahlfors,
192:
Yes, this phenomenon is unique to complex analysis. If the function is bounded at the singularity, that's enough to guarantee not only its continuity, but even infinite differentiability. I clarified this in the article.
140: 162:
I believe that your statement of Reimann's theorem is incorrect. While I can't seem to find a good description of the theorem online anywhere I am pretty sure that:
170:=1 we have a function that is obviously bounded at 0, but this is not a removable singularity. No redefinition of the Heaviside function will make this continuous. 318: 130: 313: 106: 173:
Perhaps this definition of Reimann's theorem makes more sense in the complex analysis sense, but if so you should be more specific. --anon
97: 58: 254:) exists (namely, it is 0), but this should be stated explicitly in the proof. The first two terms of the Taylor series of 33: 198: 21: 39: 83: 220:(on page 124 in the 3rd edition, 1979) gives a neat proof using the Cauchy integral formula instead. 194: 178: 105:
on Knowledge. If you would like to participate, please visit the project page, where you can join
225: 89: 73: 52: 185: 295: 235:
I agree that the proof is not very clear. I guess that the motivation for multiplying by (
307: 221: 182: 298: 229: 202: 187: 169:
b) In the example of the Heaviside functin where f(x)=0 x<0 and f(x)=1 x: -->
102: 292: 79: 15: 181:. Perhaps a different wording could make this clearer. — 101:, a collaborative effort to improve the coverage of 8: 177:I believe Riemann's theorem applies only to 19: 47: 49: 7: 95:This article is within the scope of 38:It is of interest to the following 14: 319:Low-priority mathematics articles 115:Knowledge:WikiProject Mathematics 314:Start-Class mathematics articles 118:Template:WikiProject Mathematics 82: 72: 51: 20: 135:This article has been rated as 1: 109:and see a list of open tasks. 299:11:40, 25 January 2010 (UTC) 230:05:49, 25 January 2010 (UTC) 203:01:02, 9 December 2005 (UTC) 188:22:07, 8 December 2005 (UTC) 335: 134: 67: 46: 141:project's priority scale 98:WikiProject Mathematics 28:This article is rated 179:holomorphic functions 243:) is to ensure that 158:Incorrect statement? 121:mathematics articles 258:then vanish since 90:Mathematics portal 34:content assessment 155: 154: 151: 150: 147: 146: 326: 285: 248: 218:Complex Analysis 211:Method of proof? 123: 122: 119: 116: 113: 92: 87: 86: 76: 69: 68: 63: 55: 48: 31: 25: 24: 16: 334: 333: 329: 328: 327: 325: 324: 323: 304: 303: 283: 279: 264: 246: 213: 195:Oleg Alexandrov 160: 120: 117: 114: 111: 110: 88: 81: 61: 32:on Knowledge's 29: 12: 11: 5: 332: 330: 322: 321: 316: 306: 305: 302: 301: 277: 262: 212: 209: 208: 207: 206: 205: 159: 156: 153: 152: 149: 148: 145: 144: 133: 127: 126: 124: 107:the discussion 94: 93: 77: 65: 64: 56: 44: 43: 37: 26: 13: 10: 9: 6: 4: 3: 2: 331: 320: 317: 315: 312: 311: 309: 300: 297: 294: 290: 286: 276: 272: 268: 261: 257: 253: 249: 242: 238: 234: 233: 232: 231: 227: 223: 219: 210: 204: 200: 196: 191: 190: 189: 186: 184: 180: 176: 175: 174: 171: 167: 163: 157: 142: 138: 132: 129: 128: 125: 108: 104: 100: 99: 91: 85: 80: 78: 75: 71: 70: 66: 60: 57: 54: 50: 45: 41: 35: 27: 23: 18: 17: 288: 281: 274: 270: 266: 259: 255: 251: 244: 240: 236: 217: 214: 172: 168: 164: 161: 137:Low-priority 136: 96: 62:Low‑priority 40:WikiProjects 112:Mathematics 103:mathematics 59:Mathematics 30:Start-class 308:Categories 273:) = 0 and 291:) = 0. — 222:Jowa fan 183:Caesura 139:on the 36:scale. 293:Emil 226:talk 199:talk 131:Low 310:: 296:J. 280:= 265:= 239:− 228:) 201:) 289:a 287:( 284:' 282:h 278:1 275:a 271:a 269:( 267:h 263:0 260:a 256:h 252:a 250:( 247:' 245:h 241:a 237:z 224:( 197:( 143:. 42::

Index


content assessment
WikiProjects
WikiProject icon
Mathematics
WikiProject icon
icon
Mathematics portal
WikiProject Mathematics
mathematics
the discussion
Low
project's priority scale
holomorphic functions
Caesura

22:07, 8 December 2005 (UTC)
Oleg Alexandrov
talk
01:02, 9 December 2005 (UTC)
Jowa fan
talk
05:49, 25 January 2010 (UTC)
Emil
J.
11:40, 25 January 2010 (UTC)
Categories
Start-Class mathematics articles
Low-priority mathematics articles

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.