eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Leibniz International Proceedings in Informatics
1868-8969
2010-12-14
308
316
10.4230/LIPIcs.FSTTCS.2010.308
article
Computing Rational Radical Sums in Uniform TC^0
Hunter, Paul
Bouyer, Patricia
Markey, Nicolas
Ouaknine, Joël
Worrell, James
A fundamental problem in numerical computation and computational geometry is to determine the sign of arithmetic expressions in radicals. Here we consider the simpler problem of deciding whether $\sum_{i=1}^m C_i A_i^{X_i}$ is zero for given rational numbers $A_i$, $C_i$, $X_i$. It has been known for almost twenty years that this can be decided in polynomial time. In this paper we improve this result by showing membership in uniform TC0. This requires several significant departures from Blömer's polynomial-time algorithm as the latter crucially relies on primitives, such as gcd computation and binary search, that are not known to be in TC0.
https://drops.dagstuhl.de/storage/00lipics/lipics-vol008-fsttcs2010/LIPIcs.FSTTCS.2010.308/LIPIcs.FSTTCS.2010.308.pdf
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