ACM SIGACT or SIGACT is the Association for Computing MachinerySpecial Interest Group on Algorithms and Computation Theory, whose purpose is support of research in theoretical computer science. It was founded in 1968 by Patrick C. Fischer.
SIGACT publishes a quarterly print newsletter, SIGACT News. Its online version, SIGACT News Online, is available since 1996 for SIGACT members, with unrestricted access to some features.
SIGACT sponsors or has sponsored several annual conferences.
COLT: Conference on Learning Theory, until 1999
PODC: ACM Symposium on Principles of Distributed Computing (jointly sponsored by SIGOPS)
PODS: ACM Symposium on Principles of Database Systems
POPL: ACM Symposium on Principles of Programming Languages
SOCG: ACM Symposium on Computational Geometry (jointly sponsored by SIGGRAPH), until 2014
SODA: ACM/SIAM Symposium on Discrete Algorithms (jointly sponsored by the Society for Industrial and Applied Mathematics). Two annual workshops held in conjunction with SODA also have the same joint sponsorship:
ALENEX: Workshop on Algorithms and Experiments
ANALCO: Workshop on Analytic Algorithms and Combinatorics
SPAA: ACM Symposium on Parallelism in Algorithms and Architectures
STOC: ACM Symposium on the Theory of Computing
COLT, PODC, PODS, POPL, SODA, and STOC are all listed as highly cited venues by both citeseerx and libra.