03Bxx
01 | 
03 | 
03C 03Bxx | 01 | 03 | 03C |
| 03B05 |  Classical propositional logic |
| 03B10 | Classical first-order logic |
| 03B15 | Higher-order logic and type theory |
| 03B20 | Subsystems of classical logic (including intuitionistic logic) |
| 03B22 | Abstract deductive systems |
| 03B25 | Decidability of theories and sets of sentences [See also 11U05, 12L05, 20F10] |
| 03B30 | Foundations of classical theories (including reverse mathematics) [See also 03F35] |
| 03B35 | Mechanization of proofs and logical operations [See also 68T15] |
| 03B40 | Combinatory logic and lambda-calculus [See also 68N18] |
| 03B42 | Logic of knowledge and belief |
| 03B44 | Temporal logic |
| 03B45 | Modal logic {For knowledge and belief see 03B42; for temporal logic see 03B44; for provability logic see also 03F45} |
| 03B47 | Substructural logics (including relevance, entailment, linear logic, Lambek calculus, BCK and BCI logics) {For proof-theoretic aspects see 03F52} |
| 03B48 | Probability and inductive logic [See also 60A05] |
| 03B50 | Many-valued logic |
| 03B52 | Fuzzy logic; logic of vagueness [See also 68T27, 68T37, 94D05] |
| 03B53 | Logics admitting inconsistency (paraconsistent logics, discussive logics, etc.) |
| 03B55 | Intermediate logics |
| 03B60 | Other nonclassical logic |
| 03B65 | Logic of natural languages [See also 68T50, 91F20] |
| 03B70 | Logic in computer science [See also 68-XX] |
| 03B80 | Other applications of logic |
| 03B99 | None of the above, but in this section |