Knowledge (XXG)

Unibranch local ring

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is unibranch. The notions of unibranch and geometrically unibranch points are used in some theorems in algebraic geometry. For example, there is the following result:
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there is a fundamental system of neighborhoods (in the classical topology) of
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is also a local ring. A unibranch local ring is said to be
436: 379: 197:, respectively. Suppose that the algebraic closure of 286:, then the fibers of unibranch points are connected. 241: 215: 156: 289:In EGA, the theorem is obtained as a corollary of 266: 227: 174: 150:be two integral locally noetherian schemes and 456: 399: 8: 463: 449: 406: 392: 246: 240: 214: 155: 278:connected components. In particular, if 302: 7: 417: 415: 360: 358: 324:Publications MathĂ©matiques de l'IHÉS 435:. You can help Knowledge (XXG) by 378:. You can help Knowledge (XXG) by 189:. Denote their function fields by 25: 419: 362: 117:of closed algebraic subsets of 261: 255: 175:{\displaystyle f\colon X\to Y} 166: 1: 235:is unibranch. Then the fiber 92:purely inseparable extension 513: 414: 357: 497:Commutative algebra stubs 267:{\displaystyle f^{-1}(y)} 52:(obtained by quotienting 492:Algebraic geometry stubs 125:whose intersection with 94:of the residue field of 311:Grothendieck, Alexandre 113:if for all complements 107:topologically unibranch 80:geometrically unibranch 431:-related article is a 374:–related article is a 291:Zariski's main theorem 268: 229: 228:{\displaystyle y\in Y} 176: 269: 230: 205:has separable degree 177: 239: 213: 154: 101:. A complex variety 487:Commutative algebra 429:commutative algebra 482:Algebraic geometry 372:algebraic geometry 337:10.1007/bf02684274 264: 225: 172: 29:algebraic geometry 444: 443: 387: 386: 187:dominant morphism 132:In particular, a 16:(Redirected from 504: 465: 458: 451: 423: 416: 408: 401: 394: 366: 359: 349: 348: 307: 273: 271: 270: 265: 254: 253: 234: 232: 231: 226: 181: 179: 178: 173: 66:integral closure 21: 512: 511: 507: 506: 505: 503: 502: 501: 472: 471: 470: 469: 413: 412: 355: 353: 352: 315:DieudonnĂ©, Jean 309: 308: 304: 299: 242: 237: 236: 211: 210: 152: 151: 129:is connected. 100: 77: 62:integral domain 51: 23: 22: 15: 12: 11: 5: 510: 508: 500: 499: 494: 489: 484: 474: 473: 468: 467: 460: 453: 445: 442: 441: 424: 411: 410: 403: 396: 388: 385: 384: 367: 351: 350: 301: 300: 298: 295: 263: 260: 257: 252: 249: 245: 224: 221: 218: 171: 168: 165: 162: 159: 98: 75: 49: 38:is said to be 24: 14: 13: 10: 9: 6: 4: 3: 2: 509: 498: 495: 493: 490: 488: 485: 483: 480: 479: 477: 466: 461: 459: 454: 452: 447: 446: 440: 438: 434: 430: 425: 422: 418: 409: 404: 402: 397: 395: 390: 389: 383: 381: 377: 373: 368: 365: 361: 356: 346: 342: 338: 334: 330: 326: 325: 320: 316: 312: 306: 303: 296: 294: 292: 287: 285: 281: 277: 258: 250: 247: 243: 222: 219: 216: 208: 204: 200: 196: 192: 188: 185: 169: 163: 160: 157: 149: 145: 141: 137: 135: 130: 128: 124: 120: 116: 112: 108: 104: 97: 93: 89: 85: 84:residue field 81: 74: 70: 67: 63: 59: 55: 48: 45: 41: 37: 34: 30: 19: 437:expanding it 426: 380:expanding it 369: 354: 328: 322: 305: 288: 279: 275: 274:has at most 206: 202: 198: 194: 190: 147: 143: 139: 138: 131: 126: 122: 118: 114: 110: 106: 102: 95: 87: 79: 72: 68: 53: 46: 44:reduced ring 39: 35: 26: 134:normal ring 109:at a point 476:Categories 297:References 284:birational 105:is called 64:, and the 58:nilradical 33:local ring 248:− 220:∈ 209:and that 167:→ 161:: 40:unibranch 18:Unibranch 317:(1961). 60:) is an 345:0217085 140:Theorem 82:if the 56:by its 42:if the 343:  184:proper 427:This 370:This 90:is a 433:stub 376:stub 203:K(X) 199:K(Y) 195:K(Y) 193:and 191:K(X) 146:and 142:Let 31:, a 333:doi 282:is 201:in 99:red 86:of 76:red 71:of 50:red 27:In 478:: 341:MR 339:. 331:. 329:11 327:. 321:. 313:; 293:. 182:a 464:e 457:t 450:v 439:. 407:e 400:t 393:v 382:. 347:. 335:: 280:f 276:n 262:) 259:y 256:( 251:1 244:f 223:Y 217:y 207:n 170:Y 164:X 158:f 148:Y 144:X 127:Y 123:x 119:X 115:Y 111:x 103:X 96:A 88:B 73:A 69:B 54:A 47:A 36:A 20:)

Index

Unibranch
algebraic geometry
local ring
reduced ring
nilradical
integral domain
integral closure
residue field
purely inseparable extension
normal ring
proper
dominant morphism
birational
Zariski's main theorem
Grothendieck, Alexandre
Dieudonné, Jean
"Eléments de géométrie algébrique: III. Étude cohomologique des faisceaux cohérents, Première partie"
Publications Mathématiques de l'IHÉS
doi
10.1007/bf02684274
MR
0217085
Stub icon
algebraic geometry
stub
expanding it
v
t
e
Stub icon

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