Semigroups 17 Semigroup algebras 5 Topological semigroups 5 Machine theory 3 Semigroups of operators 3 Algebra, Universal 2 Banach spaces 2 Congresses 2 Markov processes 2 Mathematics 2 Spectral theory (Mathematics) 2 Algebra 1 Algebraic varieties 1 Associative rings 1 Banach algebras 1 Commutative semigroups 1 Decomposition 1 Finite groups 1 Fuzzy sets 1 Group algebras 1 Group theory 1 Groupoids 1 History 1 Inverse semigroups 1 L1 algebras 1 Lattice theory 1 Linear operators 1 MATHEMATICS / Logic 1 Markov semigroups 1 Matrices 1