nondeterministic turing machine
21Chomsky hierarchy — Within the field of computer science, specifically in the area of formal languages, the Chomsky hierarchy (occasionally referred to as Chomsky–Schützenberger hierarchy) is a containment hierarchy of classes of formal grammars. This hierarchy of… …
22Unrestricted grammar — In formal language theory, an unrestricted grammar is a formal grammar on which no restrictions are made on the left and right sides of the grammar s productions. This is the most general class of grammars in the Chomsky–Schützenberger hierarchy …
23Leaf language — In computational complexity theory, a leaf language is a method of characterizing a complexity class by formalizing what it means for a machine to accept an input.Several complexity classes are typically defined in terms of a polynomial time… …
24Cook–Levin theorem — In computational complexity theory, the Cook–Levin theorem, also known as Cook s theorem, states that the Boolean satisfiability problem is NP complete. That is, any problem in NP can be reduced in polynomial time by a deterministic Turing… …
25True quantified Boolean formula — The language TQBF is a formal language in computer science that contains True Quantified Boolean Formulas. A fully quantified boolean formula is a formula in first order logic where every variable is quantified (or bound), using either… …
26DTIME — In computational complexity theory, DTIME (or TIME) is the computational resource of computation time for a deterministic Turing machine. It represents the amount of time (or number of computation steps) that a normal physical computer would take …
27DSPACE — For digital repositories, see DSpace. In computational complexity theory, DSPACE or SPACE is the computational resource describing the resource of memory space for a deterministic Turing machine. It represents the total amount of memory space… …
28EXPTIME — EXP redirects here; for other uses, see exp. In computational complexity theory, the complexity class EXPTIME (sometimes called EXP) is the set of all decision problems solvable by a deterministic Turing machine in O(2 p ( n )) time, where p ( n… …
29Savitch's theorem — In computational complexity theory, Savitch s theorem, proved by Walter Savitch in 1970, states that for any function f ( n ) ≥ log( n ):NSPACE(f(n)) ⊆ DSPACE(f²(n)). In other words, if a nondeterministic Turing machine can solve a problem using… …
30PP (complexity) — In complexity theory, PP is the class of decision problems solvable by a probabilistic Turing machine in polynomial time, with an error probability of less than 1/2 for all instances. The abbreviation PP refers to probabilistic polynomial time.… …
