  In this paper, we give new sparse interpolation algorithms for black box
univariate and multivariate rational functions h=f/g whose coefficients are
integers with an upper bound. The main idea is as follows: choose a proper
integer beta and let h(beta) = a/b with gcd(a,b)=1. Then f and g can be
computed by solving the polynomial interpolation problems f(beta)=ka and
g(beta)=ka for some integer k. It is shown that the univariate interpolation
algorithm is almost optimal and multivariate interpolation algorithm has low
complexity in T but the data size is exponential in n.
