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- Publications
- Influence

Understanding Model Counting for beta-acyclic CNF-formulas

- Johann Brault-Baron, F. Capelli, S. Mengel
- Computer Science, Mathematics
- STACS
- 23 May 2014

We extend the knowledge about so-called structural restrictions of $\mathrm{\#SAT}$ by giving a polynomial time algorithm for $\beta$-acyclic $\mathrm{\#SAT}$. In contrast to previous algorithms in… Expand

Constant-Delay Enumeration for Nondeterministic Document Spanners

- A. Amarilli, P. Bourhis, S. Mengel, M. Niewerth
- Computer Science
- ICDT
- 24 July 2018

We consider the information extraction approach known as document spanners, and study the problem of efficiently computing the results of the extraction from an input document, where the extraction… Expand

Knowledge Compilation Meets Communication Complexity

- S. Bova, F. Capelli, S. Mengel, Friedrich Slivovsky
- Computer Science
- IJCAI
- 9 July 2016

Choosing a language for knowledge representation and reasoning involves a trade-off between two competing desiderata: succinctness (the encoding should be small) and tractability (the language should… Expand

Lower bounds on the mim-width of some graph classes

- S. Mengel
- Mathematics, Computer Science
- Discret. Appl. Math.
- 4 August 2016

Abstract mim-width is a recent graph width measure that has seen applications in graph algorithms and problems related to propositional satisfiability. In this paper, we show linear lower bounds for… Expand

NIR Spectroscopy of the Most Massive Open Cluster in the Galaxy: Westerlund 1

- S. Mengel, L. E. Tacconi-Garman
- Physics
- 1 September 2007

Using ISAAC/VLT, we have obtained individual spectra of all NIR-bright stars in the central 2'x2' of the cluster Westerlund 1 (Wd 1) with a resolution of R~9000 at a central wavelength of 2.30… Expand

A Trichotomy in the Complexity of Counting Answers to Conjunctive Queries

- Hubie Chen, S. Mengel
- Computer Science, Mathematics
- ICDT
- 5 August 2014

Conjunctive queries are basic and heavily studied database queries; in relational algebra, they are the select-project-join queries. In this article, we study the fundamental problem of counting,… Expand

QBF as an Alternative to Courcelle's Theorem

We propose reductions to quantified Boolean formulas (QBF) as a new approach to showing fixed-parameter linear algorithms for problems parameterized by treewidth. We demonstrate the feasibility of… Expand

A Circuit-Based Approach to Efficient Enumeration

- A. Amarilli, P. Bourhis, Louis Jachiet, S. Mengel
- Computer Science, Mathematics
- ICALP
- 18 February 2017

We study the problem of enumerating the satisfying valuations of a circuit while bounding the delay, i.e., the time needed to compute each successive valuation. We focus on the class of structured… Expand

Structural Tractability of Counting of Solutions to Conjunctive Queries

- Arnaud Durand, S. Mengel
- Mathematics, Computer Science
- ICDT '13
- 8 March 2013

We explore the complexity of counting solutions to conjunctive queries, a basic class of queries from database theory. We introduce a parameter, called the quantified star size of a query ϕ, which… Expand

Enumeration on Trees under Relabelings

- A. Amarilli, P. Bourhis, S. Mengel
- Computer Science
- ICDT
- 18 September 2017

We study how to evaluate MSO queries with free variables on trees, within the
framework of enumeration algorithms. Previous work has shown how to enumerate
answers with linear-time preprocessing… Expand