| 68Q01 | General |
5 | 68Q05 | Models of computation (Turing machines, etc.) [See also 03D10, 68Q12, 81P68] |
| 68Q10 | Modes of computation (nondeterministic, parallel, interactive, probabilistic, etc.) [See also 68Q85] |
| 68Q12 | Quantum algorithms and complexity [See also 68Q05, 81P68] |
| 5 | 68Q15 | Complexity classes (hierarchies, relations among complexity classes, etc.) [See also 03D15, 68Q17, 68Q19] |
| 3 | 68Q17 | Computational difficulty of problems (lower bounds, completeness, difficulty of approximation, etc.) [See also 68Q15] |
| 68Q19 | Descriptive complexity and finite models [See also 03C13] |
| 16 | 68Q25 | Analysis of algorithms and problem complexity [See also 68W40] |
| 68Q30 | Algorithmic information theory (Kolmogorov complexity, etc.) [See also 03D32] |
| 5 | 68Q32 | Computational learning theory [See also 68T05] |
| 4 | 68Q42 | Grammars and rewriting systems |
| 4 | 68Q45 | Formal languages and automata [See also 03D05, 68Q70, 94A45] |
| 2 | 68Q55 | Semantics [See also 03B70, 06B35, 18C50] |
| 68Q60 | Specification and verification (program logics, model checking, etc.) [See also 03B70] |
| 68Q65 | Abstract data types; algebraic specification [See also 18C50] |
| 3 | 68Q70 | Algebraic theory of languages and automata [See also 18B20, 20M35] |
| 1 | 68Q80 | Cellular automata [See also 37B15] |
| 68Q85 | Models and methods for concurrent and distributed computing (process algebras, bisimulation, transition nets, etc.) |
| 68Q87 | Probability in computer science (algorithm analysis, random structures, phase transitions, etc.) [See also 68W20, 68W40] |
| 68Q99 | None of the above, but in this section |