ReST fixes and improvements
diff --git a/sage/combinat/root_system/weyl_characters.py b/sage/combinat/root_system/weyl_characters.py
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class WeylCharacter(AlgebraElement): |
212 | 212 | |
213 | 213 | def cartan_type(self): |
214 | 214 | """ |
215 | | Returns the Cartan Type. |
| 215 | Returns the Cartan type. |
216 | 216 | |
217 | 217 | EXAMPLES:: |
218 | 218 | |
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class WeylCharacter(AlgebraElement): |
315 | 315 | rule is specified, we will try to specify one. |
316 | 316 | |
317 | 317 | INPUT: |
318 | | |
319 | | |
320 | | - ``S`` - a Weyl character ring for a Lie subgroup or |
| 318 | |
| 319 | - ``S`` - a Weyl character ring for a Lie subgroup or |
321 | 320 | subalgebra |
322 | | |
323 | | - ``rule`` - a branching rule. |
| 321 | |
| 322 | - ``rule`` - a branching rule. |
324 | 323 | |
325 | 324 | |
326 | 325 | See branch_weyl_character? for more information about branching |
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class WeylCharacter(AlgebraElement): |
358 | 357 | |
359 | 358 | sage: B3 = WeylCharacterRing(['B',3]) |
360 | 359 | sage: [B3(x).is_irreducible() for x in B3.fundamental_weights()] |
361 | | [True, True, True] |
| 360 | [True, True, True] |
362 | 361 | sage: sum(B3(x) for x in B3.fundamental_weights()).is_irreducible() |
363 | | False |
| 362 | False |
364 | 363 | """ |
365 | 364 | h = self.hlist() |
366 | 365 | return len(h) is 1 and h[0][1] is 1 |
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class WeylCharacter(AlgebraElement): |
370 | 369 | Returns the symmetric square of the character. |
371 | 370 | |
372 | 371 | EXAMPLES:: |
373 | | |
| 372 | |
374 | 373 | sage: A2 = WeylCharacterRing("A2",style="coroots") |
375 | 374 | sage: A2(1,0).symmetric_square() |
376 | | A2(2,0) |
| 375 | A2(2,0) |
377 | 376 | """ |
378 | | |
379 | 377 | cmlist = self.mlist() |
380 | 378 | mdict = {} |
381 | 379 | for j in range(len(cmlist)): |
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class WeylCharacter(AlgebraElement): |
400 | 398 | |
401 | 399 | sage: A2 = WeylCharacterRing("A2",style="coroots") |
402 | 400 | sage: A2(1,0).exterior_square() |
403 | | A2(0,1) |
| 401 | A2(0,1) |
404 | 402 | """ |
405 | 403 | cmlist = self.mlist() |
406 | 404 | mdict = {} |
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class WeylCharacter(AlgebraElement): |
422 | 420 | """ |
423 | 421 | Returns: |
424 | 422 | |
425 | | 1 if the representation is real (orthogonal) |
426 | | -1 if the representation is quaternionic (symplectic) |
427 | | 0 if the representation is complex (not self dual) |
| 423 | - `1` if the representation is real (orthogonal) |
| 424 | |
| 425 | - `-1` if the representation is quaternionic (symplectic) |
| 426 | |
| 427 | - `0` if the representation is complex (not self dual) |
428 | 428 | |
429 | 429 | The Frobenius-Schur indicator of a character 'chi' |
430 | 430 | of a compact group G is the Haar integral over the |
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def WeylCharacterRing(ct, base_ring=ZZ, |
481 | 481 | character of a semisimple (or reductive) Lie group or algebra. They |
482 | 482 | form a ring, in which the addition and multiplication correspond to |
483 | 483 | direct sum and tensor product of representations. |
484 | | |
485 | | INPUT: |
486 | 484 | |
487 | | - ``ct`` - The Cartan Type |
488 | | |
489 | | OPTIONAL ARGUMENTS: |
| 485 | INPUT: |
490 | 486 | |
491 | | - ``base_ring`` - (default: `\ZZ`) |
| 487 | - ``ct`` -- The Cartan Type |
492 | 488 | |
493 | | - ``prefix`` (default an automatically generated prefix |
494 | | based on Cartan type) |
| 489 | OPTIONAL ARGUMENTS: |
495 | 490 | |
496 | | - ``cache`` - (default False) setting cache = True is a substantial |
497 | | speedup at the expense of some memory. |
498 | | |
499 | | - ``style`` - (default "lattice") can be set style = "coroots" |
500 | | to obtain an alternative representation of the elements. |
| 491 | - ``base_ring`` -- (default: `\ZZ`) |
| 492 | |
| 493 | - ``prefix`` -- (default: an automatically generated prefix based on Cartan type) |
| 494 | |
| 495 | - ``cache`` -- (default False) setting cache = True is a substantial |
| 496 | speedup at the expense of some memory. |
| 497 | |
| 498 | - ``style`` -- (default "lattice") can be set style = "coroots" |
| 499 | to obtain an alternative representation of the elements. |
501 | 500 | |
502 | 501 | If no prefix specified, one is generated based on the Cartan type. |
503 | 502 | It is good to name the ring after the prefix, since then it can |
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def WeylCharacterRing(ct, base_ring=ZZ, |
562 | 561 | ring represent characters of SL(r+1,CC), while in the default |
563 | 562 | style, they represent characters of GL(r+1,CC). |
564 | 563 | |
565 | | EXAMPLES: |
| 564 | EXAMPLES:: |
566 | 565 | |
567 | 566 | sage: A2 = WeylCharacterRing("A2") |
568 | 567 | sage: L = A2.space() |
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class WeylCharacterRing_class(Algebra): |
815 | 814 | |
816 | 815 | def cartan_type(self): |
817 | 816 | """ |
818 | | Returns the Cartan Type. |
| 817 | Returns the Cartan type. |
819 | 818 | |
820 | 819 | EXAMPLES:: |
821 | 820 | |
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def branching_rule_from_plethysm(chi, ca |
2138 | 2137 | through SO(8). The branching rule in question will |
2139 | 2138 | describe how representations of SO(8) composed with |
2140 | 2139 | this homomorphism decompose into irreducible characters |
2141 | | of SL(3). |
| 2140 | of SL(3):: |
2142 | 2141 | |
2143 | 2142 | sage: A2 = WeylCharacterRing("A2") |
2144 | 2143 | sage: A2 = WeylCharacterRing("A2", style="coroots") |
2145 | 2144 | sage: ad = A2(1,1) |
2146 | 2145 | sage: ad.degree() |
2147 | | 8 |
| 2146 | 8 |
2148 | 2147 | sage: ad.frobenius_schur_indicator() |
2149 | | 1 |
| 2148 | 1 |
2150 | 2149 | |
2151 | | This confirms that ad has degree 8 and is orthogonal, |
2152 | | hence factors through SO(8)=D4. |
| 2150 | This confirms that `ad` has degree 8 and is orthogonal, |
| 2151 | hence factors through SO(8)=D4:: |
2153 | 2152 | |
2154 | 2153 | sage: br = branching_rule_from_plethysm(ad,"D4") |
2155 | 2154 | sage: D4 = WeylCharacterRing("D4") |
2156 | 2155 | sage: [D4(f).branch(A2,rule = br) for f in D4.fundamental_weights()] |
2157 | | [A2(1,1), A2(1,1) + A2(0,3) + A2(3,0), A2(1,1), A2(1,1)] |
| 2156 | [A2(1,1), A2(1,1) + A2(0,3) + A2(3,0), A2(1,1), A2(1,1)] |
2158 | 2157 | """ |
2159 | 2158 | ct = CartanType(cartan_type) |
2160 | 2159 | if ct[0] not in ["A","B","C","D"]: |
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class WeightRingElement(AlgebraElement): |
2376 | 2375 | |
2377 | 2376 | def cartan_type(self): |
2378 | 2377 | """ |
2379 | | Returns the Cartan Type. |
| 2378 | Returns the Cartan type. |
2380 | 2379 | |
2381 | 2380 | EXAMPLES:: |
2382 | 2381 | |
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class WeightRing(Algebra): |
2619 | 2618 | |
2620 | 2619 | def cartan_type(self): |
2621 | 2620 | """ |
2622 | | Returns the Cartan Type. |
| 2621 | Returns the Cartan type. |
2623 | 2622 | |
2624 | 2623 | EXAMPLES:: |
2625 | 2624 | |