Modules (Algebra) Rings (Algebra) 6 Categories (Mathematics) 5 Associative rings 3 Congresses 3 Commutative rings 2 Torsion theory (Algebra) 2 Abelian categories 1 Algebra, Homological 1 Algebraic number theory 1 Class field theory 1 Decomposition (Mathematics) 1 Dimension theory (Algebra) 1 Divisor theory 1 Group theory 1 Radical theory 1 Representations of algebras 1