libsemigroups is a C++11 library containing implementations of several algorithms for computing finite and finitely presented semigroups. Namely: - the Froidure-Pin algorithm for computing finite semigroups; - the Todd-Coxeter algorithm for finitely presented semigroups and monoids; - the Knuth-Bendix algorithm for finitely presented semigroups and monoids; - the Schreier-Sims algorithm for permutation groups. See also: https://github.com/libsemigroups/libsemigroups