Statements (28)
| Predicate | Object |
|---|---|
| gptkbp:instanceOf |
mathematical hierarchy
|
| gptkbp:appliesTo |
arithmetical sets
subsets of natural numbers |
| gptkbp:characterizedBy |
first-order arithmetic formulas
quantifier alternations |
| gptkbp:describes |
classification of decision problems
|
| gptkbp:field |
gptkb:logic
recursion theory |
| https://www.w3.org/2000/01/rdf-schema#label |
arithmetical hierarchy
|
| gptkbp:introduced |
gptkb:Kurt_Gödel
gptkb:Stephen_Cole_Kleene |
| gptkbp:level |
recursively enumerable sets
Π_n^0 Σ_n^0 |
| gptkbp:lowerAward |
recursive sets
|
| gptkbp:notation |
Δ_n^0
Π_n^0 Σ_n^0 |
| gptkbp:relatedTo |
analytical hierarchy
polynomial hierarchy |
| gptkbp:seeAlso |
gptkb:hyperarithmetical_hierarchy
Turing degree arithmetical reducibility arithmetical set |
| gptkbp:usedIn |
gptkb:descriptive_set_theory
computability theory |
| gptkbp:bfsParent |
gptkb:Polynomial_hierarchy
|
| gptkbp:bfsLayer |
5
|