1

July 2018
LICS '18: Proceedings of the 33rd Annual ACM/IEEE Symposium on Logic in Computer Science

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 0

Downloads (6 Weeks): 1, Downloads (12 Months): 15, Downloads (Overall): 15

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The complexity of the parameterized halting problem for nondeterministic Turing machines p-Halt is known to be related to the question of whether there are logics capturing various complexity classes [10]. Among others, if p-Halt is in para-AC0, the parameterized version of the circuit complexity class AC0, then AC0, or equivalently, ...

2

November 2017
ACM Transactions on Computational Logic (TOCL): Volume 18 Issue 4, December 2017

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 0

Downloads (6 Weeks): 2, Downloads (12 Months): 48, Downloads (Overall): 48

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We study the problem of conjunctive query evaluation relative to a class of queries. This problem is formulated here as the relational homomorphism problem relative to a class of structures A , in which each instance must be a pair of structures such that the first structure is an element ...

**Keywords**:
Conjunctive queries, graph decompositions, homomorphisms, parameterized complexity

3

October 2017
Theory of Computing Systems: Volume 61 Issue 3, October 2017

**Publisher:** Springer-Verlag New York, Inc.

The embedding problem is to decide, given an ordered pair of structures, whether or not there is an injective homomorphism from the first structure to the second. We study this problem using an established perspective in parameterized complexity theory: the universe size of the first structure is taken to be ...

**Keywords**:
Embedding, Homomorphism, Parameterized space complexity

4

May 2015
ACM Transactions on Computation Theory (TOCT): Volume 7 Issue 2, May 2015

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 4

Downloads (6 Weeks): 3, Downloads (12 Months): 14, Downloads (Overall): 66

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We perform a fundamental investigation of the complexity of conjunctive query evaluation from the perspective of parameterized complexity. We classify sets of Boolean conjunctive queries according to the complexity of this problem. Previous work showed that a set of conjunctive queries is fixed-parameter tractable precisely when the set is equivalent ...

**Keywords**:
homomorphism problems, parameterized logarithmic space, Conjunctive queries, graph decompositions

5

February 2015
Archive for Mathematical Logic: Volume 54 Issue 1-2, February 2015

**Publisher:** Springer-Verlag New York, Inc.

We describe a method of forcing against weak theories of arithmetic and its applications in propositional proof complexity.

**Keywords**:
03C25, 03H15, Bounded arithmetic, Proof complexity, 03E40, 03F20, 03B70, Forcing

6

July 2014
CSL-LICS '14: Proceedings of the Joint Meeting of the Twenty-Third EACSL Annual Conference on Computer Science Logic (CSL) and the Twenty-Ninth Annual ACM/IEEE Symposium on Logic in Computer Science (LICS)

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 3

Downloads (6 Weeks): 1, Downloads (12 Months): 3, Downloads (Overall): 40

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We study the problem of conjunctive query evaluation relative to a class of queries; this problem is formulated here as the relational homomorphism problem relative to a class of structures A , wherein each instance must be a pair of structures such that the first structure is an element of ...

**Keywords**:
graph decompositions, homomorphisms, parameterized complexity, conjunctive queries

7

May 2014
ACM Transactions on Computation Theory (TOCT): Volume 6 Issue 2, May 2014

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 0

Downloads (6 Weeks): 2, Downloads (12 Months): 7, Downloads (Overall): 268

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If the class TAUT of tautologies of propositional logic has no almost optimal algorithm, then every algorithm A deciding TAUT has a hard sequence, that is, a polynomial time computable sequence witnessing that A is not almost optimal. We show that this result extends to every Π t p -complete ...

**Keywords**:
measure hypothesis, Hard sequences, optimal algorithms, optimal proof systems

8

June 2013
PODS '13: Proceedings of the 32nd ACM SIGMOD-SIGACT-SIGAI symposium on Principles of database systems

**Publisher:** ACM

**Bibliometrics**:

Citation Count: 5

Downloads (6 Weeks): 2, Downloads (12 Months): 11, Downloads (Overall): 142

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We perform a fundamental investigation of the complexity of conjunctive query evaluation from the perspective of parameterized complexity. We classify sets of boolean conjunctive queries according to the complexity of this problem. Previous work showed that a set of conjunctive queries is fixed-parameter tractable precisely when the set is equivalent ...

**Keywords**:
conjunctive queries, graph minors, logarithmic space, parameterized complexity

9

February 2013
Theory of Computing Systems: Volume 52 Issue 2, February 2013

**Publisher:** Springer-Verlag New York, Inc.

The classes W[P] and W[1] are parameterized analogues of NP in that they can be characterized by machines with restricted existential nondeterminism. These machine characterizations give rise to two natural notions of parameterized randomized algorithms that we call W[P]-randomization and W[1]-randomization. This paper develops the corresponding theory.

**Keywords**:
Derandomization, Random complexity, Parameterized complexity theory, Probability amplification, Parameterized counting complexity, Uniqueness problems

10

September 2012
IPEC'12: Proceedings of the 7th international conference on Parameterized and Exact Computation

**Publisher:** Springer-Verlag

We introduce a (new) notion of parameterized proof system. For parameterized versions of standard proof systems such as Extended Frege and Substitution Frege we compare their complexity with respect to parameterized simulations.

11

June 2012
CiE'12: Proceedings of the 8th Turing Centenary conference on Computability in Europe: how the world computes

**Publisher:** Springer-Verlag

If the class Taut of tautologies of propositional logic has no almost optimal algorithm, then every algorithm $\mathbb{A}$ deciding Taut has a polynomial time computable sequence witnessing that $\mathbb{A}$ is not almost optimal. We show that this result extends to every $\Pi_t^p$-complete problem with t ≥1; however, assuming the Measure ...

12

June 2011
CiE'11: Proceedings of the 7th conference on Models of computation in context: computability in Europe

**Publisher:** Springer-Verlag

Assume that the problem Q 0 is not solvable in polynomial time. For theories T containing a sufficiently rich part of true arithmetic we characterize T ∪{Con T } as the minimal extension of T proving for some algorithm that it decides Q 0 as fast as any algorithm B ...

13

May 2011
Theory of Computing Systems: Volume 48 Issue 4, May 2011

**Publisher:** Springer-Verlag New York, Inc.

We first present a method to rule out the existence of parameter non-increasing polynomial kernelizations of parameterized problems under the hypothesis P≠NP. This method is applicable, for example, to the problem Sat parameterized by the number of variables of the input formula. Then we obtain further improvements of corresponding results ...

**Keywords**:
Lower bound, Parameterized complexity

14

February 2010
Theory of Computing Systems: Volume 46 Issue 2, February 2010

**Publisher:** Springer-Verlag New York, Inc.

The classes of the W-hierarchy are the most important classes of intractable problems in parameterized complexity. These classes were originally defined via the weighted satisfiability problem for Boolean circuits. Here, besides the Boolean connectives we consider connectives such as majority , not-all-equal , and unique . For example, a gate ...

**Keywords**:
Parameterized complexity, W-hierarchy, Bounded weft circuits, Symmetric gates

15

July 2009
CiE '09: Proceedings of the 5th Conference on Computability in Europe: Mathematical Theory and Computational Practice

**Publisher:** Springer-Verlag

We first present a method to rule out the existence of <em>strong</em> polynomial kernelizations of parameterized problems under the hypothesis P $\ne$ NP. This method is applicable, for example, to the problem <Emphasis Type="SmallCaps">Sat</Emphasis> parameterized by the number of variables of the input formula. Then we obtain improvements of related ...

**Keywords**:
preprocessing, kernelization, Parameterized complexity

16

May 2008
IWPEC'08: Proceedings of the 3rd international conference on Parameterized and exact computation

**Publisher:** Springer-Verlag

We give a novel characterization of W[1], the most importantfixed-parameter intractability class in the W-hierarchy, using Booleancircuits that consist solely of majority gates. Such gates have a Booleanvalue of 1 if and only if more than half of their inputs have value 1. Usingmajority circuits, we define an analog of ...

17

May 2008
IWPEC'08: Proceedings of the 3rd international conference on Parameterized and exact computation

**Publisher:** Springer-Verlag

The class W[P] is a parameterized analogue of NP. Chen etal. [4] have given a machine characterization of W[P]. The correspondingmachine model gives rise to a parameterized analogue of BPP. What isthe connection between parameterized and classical derandomization?

18

September 2006
IWPEC'06: Proceedings of the Second international conference on Parameterized and Exact Computation

**Publisher:** Springer-Verlag

We prove that each parameterized counting problem in the class #[P] has a randomized fpt approximation algorithm using a W[P] oracle. Analoguous statements hold for #W[ t ] and #A[ t ] for each t ≥1. These results are parameterized analogues of a theorem due to O.Goldreich and L.Stockmeyer.