Yayoi Nakamura; Shinichi Tajima
Josai Mathematical Monographes 2 149 - 158 城西大学理学研究科 2000年
In a previous paper [4] , we studied residues of a rational function frorn a view pointof D-modules. We considered the system of linear differential equations for the algebraic10cal cohomology class associated to a given rational function. In particular, we gave therea description of the kernel space of the residue map induced by the cohomology class interms of adjoint differential operators.In this paper, we present algorithms for computing residues of a rational functionaccording to the results obtained in [4] . By exploiting properties of adjoint differentialoperators, we reduce the computation of residues of a rational function to that of a rationalfunction which has simple poles.In the first section, we recall some facts about D-modules and the algebraic localcohomology groups for the one dimensional case. In the second section, we briefly recall themain results obtained in [4] . In the third section, we describe two algorithms for computingresidues of a rational function. We utilize a formula for a squarefree denominator andproperties of a logarithmic derivative in each algorithms.NLA99: Computer Algebra : The Fourth Symposium on Nonlinear Analysis, September 16-18, 1999 Josai University, edited by Kiyoko Nishizawa (Josai University), Tomokatsu Saito (Sophia University), Teluhiko Hilano (Kanagawa Inst. Tec.)