18Cxx
18B | 
18 | 
18D 18Cxx | 18B | 18 | 18D |
| 18C05 | Equational categories [See also 03C05, 08C05] |
| 18C10 | Theories (e.g. algebraic theories), structure, and semantics [See also 03G30] |
| 18C15 | Triples (= standard construction, monad or triad), algebras for a triple, homology and derived functors for triples [See also 18Gxx] |
| 18C20 | Algebras and Kleisli categories associated with monads |
| 18C30 | Sketches and generalizations |
| 18C35 | Accessible and locally presentable categories |
| 18C50 | Categorical semantics of formal languages [See also 68Q55, 68Q65] |
| 18C99 | None of the above, but in this section |