期刊名称：Electronic Colloquium on Computational Complexity
印刷版ISSN：1433-8092
出版年度：2001
卷号：2001
出版社：Universität Trier, Lehrstuhl für Theoretische Computer-Forschung
摘要：We generalize the construction of Gabber and Galil to essentially every unimodular matrix in S L 2 ( \Z ) . It is shown that every parabolic or hyperbolic fractional linear transformation explicitly defines an expander of bounded degree and constant expansion. Thus all but a vanishingly small fraction of unimodular matrices define expanders.
