| Version | Summary | Created by | Modification | Content Size | Created at | Operation |
|---|---|---|---|---|---|---|
| 1 | Rita Xu | -- | 2237 | 2022-11-02 01:30:47 |
In descriptive complexity, a branch of computational complexity, FO is a complexity class of structures that can be recognized by formulas of first-order logic, and also equals the complexity class AC0. Descriptive complexity uses the formalism of logic, but does not use several key notions associated with logic such as proof theory or axiomatization. Restricting predicates to be from a set X yields a smaller class FO[X]. For instance, FO[Similarly, extensions of first-order logic formed by the addition of operators give rise to other well-known complexity classes. This allows the complexity of some problems to be established without reference to algorithms.