Changeset 6a07eb in git for Singular/LIB/dmodvar.lib


Ignore:
Timestamp:
Jul 22, 2010, 10:29:11 PM (13 years ago)
Author:
Viktor Levandovskyy <levandov@…>
Branches:
(u'spielwiese', '0d6b7fcd9813a1ca1ed4220cfa2b104b97a0a003')
Children:
40e810dce492e702bf0e751809ae911eaf670a12
Parents:
237b3e4eb8747703701bf0ed61e0bbd289339b4a
Message:
*levandov: keywords added, minor cleanup

git-svn-id: file:///usr/local/Singular/svn/trunk@13056 2c84dea3-7e68-4137-9b89-c4e89433aadc
File:
1 edited

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  • Singular/LIB/dmodvar.lib

    r237b3e4 r6a07eb  
    99       Jorge Martin-Morales,   jorge@unizar.es
    1010
    11 THEORY: Let K be a field of characteristic 0. Given a polynomial ring
    12       R = K[x_1,...,x_n] and a set of polynomial f_1,..., f_r in R, define
    13       F = f_1 * ... * f_r and F^s:=f_1^s_1*...*f_r^s_r for symbolic discrete
    14       (that is shiftable) variables s_1,..., s_r.
    15       The module R[1/F]*F^s has a structure of a D<S>-module, where
    16       D<S> := D(R) tensored with S over K, where
    17       - D(R) is an n-th Weyl algebra K<x_1,...,x_n,d_1,...,d_n | d_j x_j = x_j d_j +1>
    18       - S is the universal enveloping algebra of gl_r, generated by s_{ij}, where s_{ii}=s_i.
    19  One is interested in the following data:
    20  - the left ideal Ann F^s in D<S>, usually denoted by LD in the output
    21  - global Bernstein polynomial in one variable s = s_1 + ...+ s_r, denoted by bs,
    22  - its minimal integer root s0, the list of all roots of bs, which are known
    23    to be rational, with their multiplicities, which is denoted by BS
    24  - an r-tuple of operators in D<S>, denoted by PS, such that the functional equality
    25      sum(k=1 to k=r) P_k*f_k*F^s = bs*F^s holds in R[1/F]*F^s.
     11THEORY: Let K be a field of characteristic 0. Given a polynomial ring R = K[x_1,...,x_n] and
     12@* a set of polynomial f_1,..., f_r in R, define F = f_1 * ... * f_r and F^s:=f_1^s_1*...*f_r^s_r
     13@* for symbolic discrete (that is shiftable) variables s_1,..., s_r.
     14@* The module R[1/F]*F^s has a structure of a D<S>-module, where D<S> := D(R) tensored with S over K, where
     15@*   - D(R) is an n-th Weyl algebra K<x_1,...,x_n,d_1,...,d_n | d_j x_j = x_j d_j +1>
     16@*   - S is the universal enveloping algebra of gl_r, generated by s_{ij}, where s_{ii}=s_i.
     17@* One is interested in the following data:
     18@*   - the left ideal Ann F^s in D<S>, usually denoted by LD in the output
     19@*   - global Bernstein polynomial in one variable s = s_1 + ...+ s_r, denoted by bs,
     20@*   - its minimal integer root s0, the list of all roots of bs, which are known
     21@*     to be negative rational numbers, with their multiplicities, which is denoted by BS
     22@*   - an r-tuple of operators in D<S>, denoted by PS, such that the functional equality
     23@*     sum(k=1 to k=r) P_k*f_k*F^s = bs*F^s holds in R[1/F]*F^s.
    2624
    2725REFERENCES:
     
    3634AUXILIARY PROCEDURES:
    3735makeIF(F[,ORD]);    create the Malgrange ideal, associated with F = F[1],..,F[P]
     36
     37SEE ALSO: bfun_lib, dmod_lib, dmodapp_lib, gmssing_lib
     38
     39KEYWORDS: D-module; D-module structure; Bernstein-Sato polynomial for variety; global Bernstein-Sato polynomial for variety;
     40Weyl algebra; parametric annihilator for variety; Budur-Mustata-Saito approach; initial ideal approach;
    3841";
    3942
     
    362365
    363366proc bfctVarAnn (ideal F, list #)
    364 "USAGE:  bfctVarAnn(F[,gid,eng]);  F an ideal, gid,eng optional ints
    365 RETURN:  list of ideal and intvec
    366 PURPOSE: computes the roots of the Bernstein-Sato polynomial and their
    367 @*       multiplicities for an affine algebraic variety defined by
    368 @*        F = F[1],..,F[r].
     367"USAGE:  bfctVarAnn(F[,gid,eng]); F an ideal, gid,eng optional ints
     368RETURN:  list of an ideal and an intvec
     369PURPOSE: computes the roots of the Bernstein-Sato polynomial and their multiplicities
     370@*       for an affine algebraic variety defined by F = F[1],..,F[r].
    369371ASSUME:  The basering is a commutative polynomial ring in char 0.
    370372BACKGROUND: In this proc, the annihilator of f^s in D[s] is computed and then a
    371373@*       system of linear equations is solved by linear reductions in order to
    372 @*       find the minimal polynomial of S = s(1)(1) + ... + s(P)(P), following
    373 @*       the ideas by Noro.
    374 NOTE:    In the output list, the ideal contains all the roots and the invec their
    375 @*        multiplicities.
     374@*       find the minimal polynomial of S = s(1)(1) + ... + s(P)(P)
     375NOTE:    In the output list, the ideal contains all the roots and the intvec their multiplicities.
    376376@*       If gid<>0, the ideal is used as given. Otherwise, and by default, a
    377377@*       heuristically better suited generating set is used.
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