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Fundamental representation

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of the Lie group. From the expansion of a dominant weight in terms of the fundamental weights one can take a corresponding tensor product of the fundamental representations and extract one copy of the irreducible representation corresponding to that dominant weight.
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is a fundamental representation. Any finite-dimensional irreducible representation of a semisimple Lie group or Lie algebra can be constructed from the fundamental representations by a procedure due to
163:, and the two half-spin representations of the twofold cover of an even orthogonal group, the even spinor group, are fundamental representations that cannot be realized in the space of tensors. 223:, such that any dominant integral weight is a non-negative integer linear combination of the fundamental weights. The corresponding irreducible representations are the 57:. Thus in a certain sense, the fundamental representations are the elementary building blocks for arbitrary finite-dimensional representations. 92: 321: 286: 167: 240:
is sometimes loosely used to refer to a smallest-dimensional faithful representation, though this is also often called the
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representation (a term referring more to the history, rather than having a well-defined mathematical meaning).
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of the Lie group consisting of the dominant integral weights. It can be proved that there exists a set of
262: 187: 33: 37: 17: 296: 67: 8: 373: 152: 49: 137: 45: 317: 300: 282: 274: 191: 171: 156: 71: 292: 220: 212: 41: 278: 54: 367: 304: 194: 316:, Graduate Texts in Mathematics, vol. 222 (2nd ed.), Springer, 314:
Lie Groups, Lie Algebras, and Representations: An Elementary Introduction
25: 89: − 1 fundamental representations are the wedge products 160: 273:, Readings in Mathematics. Vol. 129. New York: Springer-Verlag. 197: 21: 78: 129:{\displaystyle \operatorname {Alt} ^{k}\ {\mathbb {C} }^{n}} 358:
See the proof of Proposition 6.17 in the case of SU(3)
204:. These weights are the lattice points in an orthant 95: 128: 365: 34:irreducible finite-dimensional representation 257: 115: 77:In the case of the special unitary group 48:. For example, the defining module of a 144: = 1, 2, ...,  366: 70:, all fundamental representations are 267:Representation theory. A first course 355: 343: 311: 13: 14: 390: 219:, indexed by the vertices of the 236:Outside of Lie theory, the term 177:is a fundamental representation. 170:of the simple Lie group of type 155:of the twofold cover of an odd 40:Lie group or Lie algebra whose 349: 337: 181: 1: 271:Graduate Texts in Mathematics 251: 231: 200:are indexed by their highest 7: 225:fundamental representations 188:irreducible representations 60: 10: 395: 238:fundamental representation 30:fundamental representation 279:10.1007/978-1-4612-0979-9 312:Hall, Brian C. (2015), 74:of the defining module. 168:adjoint representation 130: 379:Representation theory 148: − 1. 131: 18:representation theory 93: 68:general linear group 217:fundamental weights 153:spin representation 138:alternating tensors 66:In the case of the 50:classical Lie group 136:consisting of the 126: 46:fundamental weight 323:978-0-387-40122-5 288:978-0-387-97495-8 111: 72:exterior products 386: 359: 353: 347: 346:Proposition 8.35 341: 326: 308: 192:simply-connected 157:orthogonal group 135: 133: 132: 127: 125: 124: 119: 118: 109: 105: 104: 394: 393: 389: 388: 387: 385: 384: 383: 364: 363: 362: 354: 350: 342: 338: 324: 289: 259:Fulton, William 254: 234: 210: 184: 175: 120: 114: 113: 112: 100: 96: 94: 91: 90: 63: 12: 11: 5: 392: 382: 381: 376: 361: 360: 348: 335: 334: 333: 329: 328: 322: 309: 287: 253: 250: 233: 230: 221:Dynkin diagram 213:weight lattice 208: 183: 180: 179: 178: 173: 164: 149: 123: 117: 108: 103: 99: 75: 62: 59: 42:highest weight 9: 6: 4: 3: 2: 391: 380: 377: 375: 372: 371: 369: 357: 352: 345: 340: 336: 331: 330: 325: 319: 315: 310: 306: 302: 298: 294: 290: 284: 280: 276: 272: 268: 264: 260: 256: 255: 249: 247: 243: 239: 229: 226: 222: 218: 214: 207: 203: 199: 196: 193: 189: 176: 169: 165: 162: 158: 154: 150: 147: 143: 139: 121: 106: 101: 97: 88: 84: 82: 76: 73: 69: 65: 64: 58: 56: 51: 47: 43: 39: 35: 31: 27: 23: 19: 351: 339: 313: 266: 245: 241: 237: 235: 224: 216: 205: 185: 145: 141: 86: 80: 29: 26:Lie algebras 15: 263:Harris, Joe 182:Explanation 55:Élie Cartan 374:Lie groups 368:Categories 252:References 232:Other uses 161:spin group 159:, the odd 38:semisimple 22:Lie groups 356:Hall 2015 344:Hall 2015 305:246650103 198:Lie group 107:⁡ 332:Specific 265:(1991). 246:defining 242:standard 61:Examples 297:1153249 211:in the 202:weights 195:compact 320:  303:  295:  285:  140:, for 110:  85:, the 32:is an 190:of a 44:is a 36:of a 318:ISBN 301:OCLC 283:ISBN 186:The 166:The 151:The 28:, a 24:and 275:doi 244:or 98:Alt 79:SU( 20:of 16:In 370:: 299:. 293:MR 291:. 281:. 269:. 261:; 327:. 307:. 277:: 209:+ 206:Q 174:8 172:E 146:n 142:k 122:n 116:C 102:k 87:n 83:) 81:n

Index

representation theory
Lie groups
Lie algebras
irreducible finite-dimensional representation
semisimple
highest weight
fundamental weight
classical Lie group
Élie Cartan
general linear group
exterior products
SU(n)
alternating tensors
spin representation
orthogonal group
spin group
adjoint representation
E8
irreducible representations
simply-connected
compact
Lie group
weights
weight lattice
Dynkin diagram
Fulton, William
Harris, Joe
Graduate Texts in Mathematics
doi
10.1007/978-1-4612-0979-9

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