Karp reductions

E519560

Karp reductions are polynomial-time many-one reductions used in computational complexity theory to show that one decision problem is at least as hard as another, central to defining NP-completeness.

All labels observed (2)

Label Occurrences
Karp reductions canonical 1
Levin reduction 1

How this entity was disambiguated

Statements (50)

Predicate Object
instanceOf concept in computational complexity theory
polynomial-time many-one reduction
reduction between decision problems
alsoKnownAs P-time many-one reduction
polynomial-time many-one reduction
assumptionOnEncoding instances are encoded as finite strings over a fixed alphabet
canonicalExampleFrom SAT
canonicalExampleTo CLIQUE
HAMILTONIAN CYCLE
VERTEX COVER
category many-one reduction
closureProperty transitive
codomain decision problem
complexityClassContext NP
NP-complete
P
computabilityRequirement reduction function must be computable in polynomial time
contrastWith Cook reduction
Turing reduction
linked to: Turing reducibility
domain decision problem
ensuresProperty if B is in P and A ≤_m^P B then A is in P
field computational complexity theory
formalDefinition a function f from instances of problem A to instances of problem B such that x is in A if and only if f(x) is in B and f is computable in polynomial time
impliesHardness if A Karp-reduces to B and A is NP-hard then B is NP-hard
importance standard notion of reduction for NP-completeness proofs
influencedBy earlier notions of reducibility in recursion theory
introducedBy Richard M. Karp
linked to: Richard Karp
introducedInWork "Reducibility Among Combinatorial Problems"
introducedInYear 1972
logicalForm single call transformation from one instance to another
mappingType many-one reduction
namedAfter Richard M. Karp
linked to: Richard Karp
NPCompleteDefinitionRole a problem is NP-complete if it is in NP and every problem in NP Karp-reduces to it
preservesMembership x ∈ A iff f(x) ∈ B
problemType decision problems with yes/no answers
relatedConcept Cook–Levin theorem
complete problems for NP
polynomial-time reduction
relationToNPCompleteness used to define NP-complete problems
requires polynomially bounded output size
strongerThan polynomial-time Turing reduction in terms of restriction
symbolicNotation ≤_m^P
timeComplexityConstraint polynomial time
transitivityDescription if A ≤_m^P B and B ≤_m^P C then A ≤_m^P C
usedFor comparing hardness of decision problems
proving NP-completeness
showing one problem is at least as hard as another
usedIn classification of NP-complete problems
reductions between SAT and other problems
usedToShow NP-hardness of optimization problems via decision versions

How these facts were elicited

Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Richard Karp notableConcept Karp reductions
Leonid Levin notableFor Levin reduction
linked to: Karp reductions