Sökning: "Hardness of approximation"

Visar resultat 1 - 5 av 23 avhandlingar innehållade orden Hardness of approximation.

  1. 1. Hardness of Constraint Satisfaction and Hypergraph Coloring : Constructions of Probabilistically Checkable Proofs with Perfect Completeness

    Författare :Sangxia Huang; Johan Håstad; Rishi Saket; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Combinatorial optimization; approximation; inapproximability; hardness; probabilistically checkable proofs; pcp; perfect completeness; boolean constraint satisfaction problem; csp; graph coloring; hypergraph coloring; direct sum; superposition; label cover; Computer Science; Datalogi;

    Sammanfattning : A Probabilistically Checkable Proof (PCP) of a mathematical statement is a proof written in a special manner that allows for efficient probabilistic verification. The celebrated PCP Theorem states that for every family of statements in NP, there is a probabilistic verification procedure that checks the validity of a PCP proof by reading only 3 bits from it. LÄS MER

  3. 2. Label Cover Reductions for Unconditional Approximation Hardness of Constraint Satisfaction

    Författare :Cenny Wenner; Johan Håstad; Viggo Kann; Irit Dinur; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Combinatorial Optimization; Complexity Theory; Approximation; Approximability; Inapproximability; Computational Hardness; NP; Optimization; Constraint Satisfaction; Kombinatorisk optimering; Komplexitetsteori; Beräkningsteori; Approximation; Approximerbarhet; Beräkningssvårighet; NP; Optimering; Vilkorssatisfiering; Vilkorsuppfyllning; Vilkorstillfredställand; datalogi; Computer Science;

    Sammanfattning : Combinatorial optimization include such tasks as finding the quickest route to work, scheduling jobs to specialists, and placing bus stops so as to minimize commuter times. We consider problems where one is given a collection of constraints with the objective of finding an assignment satisfying as many constraints as possible, also known as Constraint Satisfaction Problems (CSPs). LÄS MER

  4. 3. Topics in Hardness of Approximation and Social Choice Theory

    Författare :Marcus Isaksson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hardness of approximation; social choice theory; Gibbard-Satterthwaite; max-q-cut; Condorcet voting; linear threshold functions.; Hardness of approximation;

    Sammanfattning : Tools from Fourier analysis of Boolean functions have commonly been used to prove results both in hardness of approximation in computer science and in the study of voting schemes in social choice theory. In this thesis we consider various topics in both these contexts. LÄS MER

  5. 4. Label Cover Reductions for Unconditional Approximation Hardness of Constraint Satisfaction

    Författare :Cenny Wenner; Johan Håstad; Irit Dinur; Numerical Analysis and Computer Science (NADA) Faculty of Science Stockholm University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optimization; NP; Approximation; Approximability; Inapproximability; Constraint Satisfaction; CSP; Boolean Analysis; Satisfiability; SAT; Acyclic Subgraph; Betweenness; Unique Games; Computer Science; Datalogi;

    Sammanfattning : Problem solving is an integral aspect of modern society and includes such tasks as picking the fastest route to work, optimizing a production line, scheduling computer tasks, placing new bus stops, or picking a meal from available ingredients.We study the hardness of solving Constraint Satisfaction Problems (CSPs). LÄS MER

  7. 5. Hardness of Approximating Constraint Satisfaction Problems and Their Variants in Presence of Additional Structural Assumptions

    Författare :Aleksa Stankovic; Johan Håstad; Per Austrin; Luca Trevisan; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hardness of Approximation; Approximation Algorithms; Label Cover; Vertex Cover; Unique Games Conjecture; Max-3-Lin; Universal Factor Graphs; Regular Constraint Satisfaction Problems; Inapproximerbarhet; Approximationsalgoritm; Label Cover; Vertex Cover; Unique Games Conjecture; Max-3-Lin; Universell Faktorgraf; Regelbundna Begränsningsproblem; Datalogi; Computer Science;

    Sammanfattning : This thesis studies how the approximability of some fundamental computational problems is affected by some additional requirements on the structure of the inputs. The problems studied in this thesis belong or are closely related to constraint satisfaction problems (CSPs), which are considered to be one of the most fundamental problems in theoretical computer science. LÄS MER