Full partial fraction decomposition of rational functions
Manuel Bronstein, Bruno Salvy · 1993
We describe a rational algorithm that computes the full partial fraction expansion of a rational function over the algebraic closure of its field of definition. The algorithm uses only gcd operations over the initial field but the resulting decomposition is expressed with linear denominators. We give examples from its Axiom and Maple implementations. Introduction The partial fraction decomposition of a rational function is a form where both the local and global behaviour of the function are easy to find. This is used when computing a primitive by hand, or any linear operation which is most easily done on a pole. An example is the efficient computation of asymptotic expansion of the solutions of a linear recurrence with constant coefficients [4]. Let f = A=D be a rational function in some field K(z). By the fundamental theorem of algebra, it is clear that f admits a partial fraction decomposition of the form f = P + X D(ff)=0 n ff X i=1 b ff;i (z \\Gamma ff) i ; (1) where P is...