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Complete variety

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2 and higher. While any complete nonsingular surface is projective, there exist nonsingular complete varieties in dimension 3 and higher which are not projective. The first examples of non-projective complete varieties were given by
81: 433: 468: 423: 363: 159: 131: 46: 158:. An intuitive justification of "complete", in the sense of "no missing points", can be given on the basis of the 443: 355: 251:
Zariski, Oscar (1958). "Introduction to the Problem of Minimal Models in the Theory of Algebraic Surfaces".
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is compact if and only if the above projection map is closed with respect to topological products.
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The image of a complete variety is closed and is a complete variety. A closed
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on it will have more closed sets (except in very simple cases). See also
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A complex variety is complete if and only if it is compact as a
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The morphism taking a complete variety to a point is a
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onto closed sets). This can be seen as an analogue of
57: 122:The most common example of a complete variety is a 75: 496: 453:(1977). "Appendix B. Example 3.4.1. (Fig.24)". 358:, vol. 52, New York: Springer-Verlag, 449: 344: 306: 321: 284: 282: 431: 398: 250: 147:of positive dimension is not complete. 497: 325:On the theory of birational blowing-up 288: 404:The red book of varieties and schemes 380: 279: 112:of a complete variety is complete. 13: 14: 516: 160:valuative criterion of properness 128:complete non-projective varieties 253:American Journal of Mathematics 315: 244: 198: 76:{\displaystyle X\times Y\to Y} 67: 1: 356:Graduate Texts in Mathematics 328:(thesis). Harvard University. 237: 434:"Complete algebraic variety" 38:, such that for any variety 7: 439:Encyclopedia of Mathematics 169: 10: 521: 336: 322:Hironaka, Heisuke (1960). 289:Nagata, Masayoshi (1958). 29:complete algebraic variety 98:in algebraic geometry: a 16:Type of algebraic variety 381:Milne, James S. (2009), 191: 117:complex-analytic variety 432:Danilov, V.I. (2001) , 308:10.1215/ijm/1255454111 77: 162:, which goes back to 126:, but there do exist 78: 55: 505:Algebraic varieties 218:does not carry the 181:Theorem of the cube 23:, in particular in 456:Algebraic Geometry 384:Algebraic geometry 351:Algebraic Geometry 222:, in general; the 154:, in the sense of 124:projective variety 73: 25:algebraic geometry 470:978-0-387-90244-9 451:Hartshorne, Robin 425:978-3-540-63293-1 365:978-0-387-90244-9 346:Hartshorne, Robin 100:topological space 33:algebraic variety 512: 490: 446: 428: 394: 393: 392: 376: 343:Section II.4 of 330: 329: 319: 313: 312: 310: 295:Illinois J. Math 286: 277: 276: 248: 231: 224:Zariski topology 220:product topology 217: 202: 164:Claude Chevalley 141:Heisuke Hironaka 137:Masayoshi Nagata 104: 82: 80: 79: 74: 41: 37: 520: 519: 515: 514: 513: 511: 510: 509: 495: 494: 493: 471: 461:Springer-Verlag 426: 408:Springer-Verlag 397:Section I.9 of 390: 388: 366: 339: 334: 333: 320: 316: 287: 280: 265:10.2307/2372827 249: 245: 240: 235: 234: 228:Segre embedding 209: 203: 199: 194: 172: 152:proper morphism 102: 56: 53: 52: 39: 35: 17: 12: 11: 5: 518: 508: 507: 492: 491: 469: 447: 429: 424: 416:10.1007/b62130 400:Mumford, David 395: 377: 364: 340: 338: 335: 332: 331: 314: 278: 242: 241: 239: 236: 233: 232: 196: 195: 193: 190: 189: 188: 183: 178: 171: 168: 84: 83: 72: 69: 66: 63: 60: 15: 9: 6: 4: 3: 2: 517: 506: 503: 502: 500: 488: 484: 480: 476: 472: 466: 462: 458: 457: 452: 448: 445: 441: 440: 435: 430: 427: 421: 417: 413: 409: 405: 401: 396: 386: 385: 379:Chapter 7 of 378: 375: 371: 367: 361: 357: 353: 352: 347: 342: 341: 327: 326: 318: 309: 304: 300: 296: 292: 285: 283: 274: 270: 266: 262: 258: 254: 247: 243: 229: 225: 221: 216: 212: 207: 201: 197: 187: 184: 182: 179: 177: 174: 173: 167: 165: 161: 157: 156:scheme theory 153: 148: 146: 142: 138: 133: 129: 125: 120: 118: 113: 111: 106: 101: 97: 93: 89: 70: 64: 61: 58: 51: 50: 49: 48: 45: 34: 30: 26: 22: 455: 437: 403: 389:, retrieved 383: 349: 324: 317: 298: 294: 256: 252: 246: 214: 210: 200: 186:Fano variety 176:Chow's lemma 149: 145:affine space 121: 114: 107: 85: 28: 18: 301:: 490–498. 259:: 146–184. 96:compactness 92:closed sets 90:(i.e. maps 21:mathematics 487:0367.14001 391:2010-08-04 238:References 132:dimensions 110:subvariety 88:closed map 44:projection 444:EMS Press 387:, v. 5.20 204:Here the 68:→ 62:× 499:Category 402:(1999), 348:(1977), 208:variety 170:See also 47:morphism 479:0463157 374:0463157 337:Sources 273:2372827 206:product 485:  477:  467:  422:  372:  362:  271:  31:is an 269:JSTOR 192:Notes 143:. An 86:is a 465:ISBN 420:ISBN 360:ISBN 139:and 42:the 27:, a 483:Zbl 412:doi 303:doi 261:doi 130:in 19:In 501:: 481:. 475:MR 473:. 463:. 442:, 436:, 418:, 410:, 370:MR 368:, 354:, 297:. 293:. 281:^ 267:. 257:80 255:. 213:× 166:. 119:. 489:. 414:: 311:. 305:: 299:2 275:. 263:: 230:. 215:Y 211:X 103:X 71:Y 65:Y 59:X 40:Y 36:X

Index

mathematics
algebraic geometry
algebraic variety
projection
morphism
closed map
closed sets
compactness
topological space
subvariety
complex-analytic variety
projective variety
complete non-projective varieties
dimensions
Masayoshi Nagata
Heisuke Hironaka
affine space
proper morphism
scheme theory
valuative criterion of properness
Claude Chevalley
Chow's lemma
Theorem of the cube
Fano variety
product
product topology
Zariski topology
Segre embedding
doi
10.2307/2372827

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