# Category: Reduction (complexity)

Enumeration reducibility
In computability theory and computational complexity theory, enumeration reducibility is a method of reduction that determines if there is some effective procedure for determining enumerability betwee
Log-space reduction
In computational complexity theory, a log-space reduction is a reduction computable by a deterministic Turing machine using logarithmic space. Conceptually, this means it can keep a constant number of
Polynomial-time reduction
In computational complexity theory, a polynomial-time reduction is a method for solving one problem using another. One shows that if a hypothetical subroutine solving the second problem exists, then t
Approximation-preserving reduction
In computability theory and computational complexity theory, especially the study of approximation algorithms, an approximation-preserving reduction is an algorithm for transforming one optimization p
Computable isomorphism
In computability theory two sets of natural numbers are computably isomorphic or recursively isomorphic if there exists a total bijective computable function with . By the Myhill isomorphism theorem,
L-reduction
In computer science, particularly the study of approximation algorithms, an L-reduction ("linear reduction") is a transformation of optimization problems which linearly preserves approximability featu
First-order reduction
In computer science, a first-order reduction is a very strong type of reduction between two computational problems in computational complexity theory. A first-order reduction is a reduction where each
Many-one reduction
In computability theory and computational complexity theory, a many-one reduction (also called mapping reduction) is a reduction which converts instances of one decision problem into instances of a se
Parsimonious reduction
In computational complexity theory and game complexity, a parsimonious reduction is a transformation from one problem to another (a reduction) that preserves the number of solutions. Informally, it is
Polynomial-time counting reduction
In the computational complexity theory of counting problems, a polynomial-time counting reduction is a type of reduction (a transformation from one problem to another) used to define the notion of com
Truth-table reduction
In computability theory, a truth-table reduction is a reduction from one set of natural numbers to another.As a "tool", it is weaker than Turing reduction, since not every Turing reduction between set