Universal algebra

Summary

Universal algebra is the part of algebra that studies algebraic structures in general, rather than groups, rings or lattices one at a time. Its objects are sets with a family of finitary operations, described by a signature. It treats homomorphisms, subalgebras, congruences and products for all such structures at once. Its central results, such as Birkhoff's HSP theorem, describe the classes of algebras defined by identities.