Changeset 4a54b7 in git for Singular/LIB/ratgb.lib
- Timestamp:
- Oct 13, 2010, 2:37:12 PM (14 years ago)
- Branches:
- (u'fieker-DuVal', '117eb8c30fc9e991c4decca4832b1d19036c4c65')(u'spielwiese', 'd08f5f0bb3329b8ca19f23b74cb1473686415c3a')
- Children:
- 9c5f5282789f1d596251d632f870343d23c5e7c0
- Parents:
- e82bb379fa5d86aee55251282d46ad9638fa2ebc
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Singular/LIB/ratgb.lib
re82bb37 r4a54b7 10 10 The operators are usually denoted by @code{d1,..,dM}. 11 11 12 Assume, that A is a @code{G}-algebra, then the set @code{S=R-{0}} is multiplicatively 12 Assume, that A is a @code{G}-algebra, then the set @code{S=R-{0}} is multiplicatively 13 13 closed Ore set in A. 14 14 That is, for any s in S and a in A, there exist t in S and b in A, such that @code{sa=bt}. 15 In other words, one can transform any left fraction into the right fraction. 15 In other words, one can transform any left fraction into the right fraction. 16 16 The algebra @code{A_S} is called an Ore localization of A with respect to S. 17 17 18 This library provides Groebner basis procedure for A_S, performing polynomial (that is 18 This library provides Groebner basis procedure for A_S, performing polynomial (that is 19 19 fraction-free) computations only. Note, that there is ongoing development of the 20 20 subsystem called Singular:Locapal, which will provide yet another approach to Groebner … … 24 24 We will assume that the variables @code{x1,...,xN} from above (which will become invertible 25 25 in the localization) come as the first block in the basering. 26 Moreover, the ordering on the basering must be an antiblock ordering, that is its 26 Moreover, the ordering on the basering must be an antiblock ordering, that is its 27 27 matrix form has the left upper @code{NxN} block zero. Here is a recipy to create such 28 28 an ordering easily: use 'a(w)' definitions of the ordering N times with intvecs @code{w_i} … … 31 31 32 32 Guide: with this library, it is possible 33 - to compute a Groebner basis of an ideal or a submodule in the 'rational' 34 Ore localization D = A_S 33 - to compute a Groebner basis of an ideal or a submodule in the 'rational' 34 Ore localization D = A_S 35 35 - to compute a dimension of associated graded submodule (called D-dimension) 36 - to compute a vector space dimension over Quot(R) of a submodule of 36 - to compute a vector space dimension over Quot(R) of a submodule of 37 37 D-dimension 0 (so called D-finite submodule) 38 38 - to compute a basis over Quot(R) of a D-finite submodule … … 88 88 ASSUME: the variables of basering are organized in two blocks and 89 89 - the first block of length n contains the elements with respect to which one localizes, 90 - the basering is equipped with the elimination block ordering for the variables 90 - the basering is equipped with the elimination block ordering for the variables 91 91 in the second block 92 92 NOTE: the output ring C is commutative. The ideal @code{rGBid} in C … … 359 359 // this ordering is an antiblock ordering, as it must be 360 360 def S = Weyl(); setring S; 361 // the ideal I below annihilates parametric Appel F4 function 361 // the ideal I below annihilates parametric Appel F4 function 362 362 // where we set parameters to a=-2, b=-1 and d=0 363 363 ideal I = … … 464 464 // this ordering is an antiblock ordering, as it must be 465 465 def S = Weyl(); setring S; 466 // the ideal I below annihilates parametric Appel F4 function 466 // the ideal I below annihilates parametric Appel F4 function 467 467 // where we set parameters to a=-2, b=-1 and d=0 468 468 ideal I = … … 470 470 y*Dy*(y*Dy-1) - y*(x*Dx+y*Dy-2)*(x*Dx+y*Dy-1); 471 471 472 // the ideal J below annihilates parametric Appel F4 function 472 // the ideal J below annihilates parametric Appel F4 function 473 473 // where we set parameters to a=0, b=-1, c=0, d=0 474 474 475 ideal J = 475 ideal J = 476 476 x*Dx*(x*Dx-1) - x*(x*Dx+y*Dy)*(x*Dx+y*Dy-1), 477 477 y*Dy*(y*Dy-1) - y*(x*Dx+y*Dy)*(x*Dx+y*Dy-1); … … 479 479 module M = I*gen(1), J*gen(2); 480 480 481 // harder modification: M = M, Dx*gen(1) + Dy*gen(2); 481 // harder modification: M = M, Dx*gen(1) + Dy*gen(2); 482 482 // gives K(x,y)-dim 3 483 483
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