Stefan Szeider | AC Group | TU Wien

FWF Cluster of Excellence: Bilateral Artificial Intelligence

Mon, 01 Jan 2024 00:00:00 +0000

🌐 Visit the official FWF Project Radar Page

The project Bilateral AI aims at lifting artificial intelligence (AI) to the next level. Current AI systems are in a sense narrow. They center on a specific application or task such as object or speech recognition. Our project will combine two of the most important types of AI which have been developed separately so far: symbolic and sub-symbolic AI. While symbolic AI works with clearly defined logical rules, sub-symbolic AI (such as ChatGPT) is based on training a machine with the help of large datasets to create intelligent behavior. This integration, resulting in a Broad AI, is intended to mirror something that humans do naturally: the simultaneous use of cognition and reasoning skills. But what exactly is Broad AI? As opposed to Narrow AI, which is characterized by task specific skills, Broad AI aims at solving a wide array of problems, rather than being limited to a single task or domain. By combining sub-symbolic AI (machine learning, ML) with symbolic AI (knowledge representation and reasoning, KRR), Bilateral AI provides the means to develop the foundations of the capabilities and skill acquisition for problem solving by a Broad AI. Harnessing the full potential of both symbolic and sub-symbolic approaches can open new avenues for AI that are better at solving new problems, adapting to a wide variety of environments, having better reasoning skills, and being more efficient in terms of both computation and data use. These key features allow for a vast range of use cases for Broad AI, starting with drug development and medicine, over planning and scheduling, to autonomous traffic management and recommendation systems. With fairness, transparency, and explainability as top priorities, developing Broad AI is also essential for addressing ethical concerns and ensuring a positive impact on our society. These concerns play a central role as cross-cutting aspect in our project. The Broad AI resulting from the bilateral AI approach would use its own sensory perceptions to perform abstractions and engage in a logical thinking process. The AI could then, for example, organize a trip, minimize carbon emissions, or renovate a house as cost- effectively and ecologically as possible. In other words, AI could perform complex planning taking all aspects into account. Sepp Hochreiter, Director of Research: Broad AI could potentially improve our everyday lives as well as system-relevant aspects and processes - such as energy, transportation and healthcare - by becoming more environmentally sustainable, efficient and resource-friendly.

A General Theoretical Framework for Learning Smallest Interpretable Models

Thu, 01 Jan 2026 00:00:00 +0000

Agentic Neurosymbolic Collaboration for Mathematical Discovery: A Case Study in Combinatorial Design

Thu, 01 Jan 2026 00:00:00 +0000

Algorithm Selection with Zero Domain Knowledge via Text Embeddings

Thu, 01 Jan 2026 00:00:00 +0000

ASP-Bench: From Natural Language to Logic Programs

Thu, 01 Jan 2026 00:00:00 +0000

Backdoors to Satisfaction Continued

Thu, 01 Jan 2026 00:00:00 +0000

Computing Probabilistic Explanations for ML Models: Fixed-Parameter Algorithms

Thu, 01 Jan 2026 00:00:00 +0000

ContReAct: A Feedback-Based Architecture for Continuous Agentic Operation

Thu, 01 Jan 2026 00:00:00 +0000

CP-Agent: Agentic Constraint Programming

Thu, 01 Jan 2026 00:00:00 +0000

Formally Verified Graph Generation with SAT Modulo Symmetries and Lean

Thu, 01 Jan 2026 00:00:00 +0000

From Data Completion to Problems on Hypercubes: A Parameterized Analysis of the Independent Set Problem

Thu, 01 Jan 2026 00:00:00 +0000

Graph Choosability via SAT: Beyond the Nullstellensatz

Thu, 01 Jan 2026 00:00:00 +0000

LLM-Guided Graph Generation for Structure-Based Local Improvement Methods

Thu, 01 Jan 2026 00:00:00 +0000

LLM-Guided Semantic Vtrees for SDD Compilation

Thu, 01 Jan 2026 00:00:00 +0000

MaxSAT-Based Compression for Tsetlin Machines

Thu, 01 Jan 2026 00:00:00 +0000

Neurosymbolic Discovery of Algebraic Graph Constructions

Thu, 01 Jan 2026 00:00:00 +0000

OBDDs, SDDs, and Circuits of Bounded Width: Completeness Matters

Thu, 01 Jan 2026 00:00:00 +0000

Smart Cubing for Graph Search: A Comparative Study

Thu, 01 Jan 2026 00:00:00 +0000

Streamliners for Answer Set Programming

Thu, 01 Jan 2026 00:00:00 +0000

Synthesizing Feature Extractors: An Agentic Approach for Algorithm Selection

Thu, 01 Jan 2026 00:00:00 +0000

VIPR Certificate Construction from Black-Box ILP Solvers

Thu, 01 Jan 2026 00:00:00 +0000

Herbert Fleischner (1944-2025)

Wed, 05 Nov 2025 00:00:00 +0000

We are deeply saddened by the passing of Herbert Fleischner, friend and colleague. Herbert was a distinguished graph theorist whose work, including the famous Fleischner’s theorem, shaped the field.

Herbert Fleischner, who passed away on October 7, 2025, in Vienna, was a mathematician whose work shaped our understanding of graph theory. Born in London on January 29, 1944, he moved to Vienna with his parents in 1946 and remained connected to the city throughout his life, even as his career took him across continents.

Herbert studied mathematics and physics at the University of Vienna under Nikolaus Hofreiter and Edmund Hlawka, earning his PhD in 1968. His dissertation focused on Eulerian and Hamiltonian graphs, topics that would define his research for decades. While Hlawka was his official supervisor, Herbert Izbicki provided the actual guidance, being a graph theorist himself.

His most influential contribution came early in his career. In 1971, he submitted a proof showing that the square of every two-connected graph contains a Hamiltonian cycle. Published in 1974, this result became known as Fleischner’s theorem and remains a cornerstone in graph theory. The elegance of the statement, which is simple to understand yet challenging to prove, captured something essential about the structure of graphs.

Another milestone in his research was solving Paul Erdős’s “Cycle plus Triangles” problem, work he accomplished in collaboration with Michael Stiebitz. That paper appeared in 1992 in a special issue honoring Julius Petersen. His Erdős number was 2.

Herbert’s career path was anything but conventional. After positions at SUNY Binghamton and a year at the Institute for Advanced Study in Princeton, he spent most of his professional life at the Austrian Academy of Sciences, from 1973 to 2002. However, he was always on the move, traveling to Memphis, MIT, and making multiple stays in Canada, as well as regularly visiting Texas A&M. In 2003, Herbert joined TU Wien, where he continued his research as the PI of projects from the Austrian Science Funds (FWF) as part of what is now the Algorithms and Complexity Group at the Institute of Logic and Computation. In total, Herbert secured four grants from the Austrian Science Fund (FWF), one while at the Austrian Academy of Sciences, where I collaborated as a PhD student, and three at TU Wien, in collaboration with my colleague Günther Raidl. Herbert worked on graph theoretical problems until his last days.

What set Herbert apart was his commitment to mathematics education in developing countries. From the late 1990s to 2012, he worked extensively with the University of Zimbabwe, serving as the main lecturer and project coordinator for an M.Sc. program in academic staff development (1997-1999, sponsored by UNESCO and the Austrian Development Cooperation), and subsequently making regular visits for teaching and supervision through 2012. He did similar work at the University of Dar es Salaam in Tanzania from 2003 to 2009. From 2001 to 2007, he chaired the Committee for Developing Countries of the European Mathematical Society, working to strengthen mathematical research and education where it was needed most.

He supervised nine PhD students. I was fortunate to be among them. Herbert was genuinely open to ideas and topics. Some of my best memories are standing with him in front of a blackboard, working through an argument together. He’d draw a graph, we’d discuss where it might lead, and he’d push for thoroughness: every case would be considered, and every detail would be checked. Those sessions taught me what mathematical thinking, where intuition meets precision, actually looks like.

He organized workshops on the Matthews-Sumner Conjecture with Zdeněk Ryjáček in the Czech Republic, bringing together researchers who shared his passion for cycle-related problems in graphs.

Herbert wrote two volumes on Eulerian graphs, published in 1990 and 1991, that became standard references. They were translated into Russian and Chinese, a testament to their lasting value. Over his career, he published more than 90 papers. He also found an unexpected connection between mathematics and art through his friendship with painter Robert Lettner. They collaborated on a series called “mutations,” where mathematical graphs were transformed into paintings.

Herbert spoke German, English, and Russian fluently. Beyond his professional achievements, he raised his son, Michael, born in 1974, as a single father during a time when this was uncommon. Later in life, he found happiness with his wife Renata, whom he married in 2005.

Herbert Fleischner spent his life building structures: mathematical structures in graph theory, educational structures in developing countries, collaborative structures across continents. He understood that mathematics isn’t just about theorems; it’s about creating communities where ideas can grow.

We’ll miss him.

Algorithms and Complexity Group, TU Wien

Analyzing Reformulation Performance in Core-Guided MaxSAT Solving

Wed, 01 Jan 2025 00:00:00 +0000

Balancing Latin Rectangles with LLM-Generated Streamliners

Wed, 01 Jan 2025 00:00:00 +0000

Breaking Symmetries in Quantified Graph Search: A Comparative Study

Wed, 01 Jan 2025 00:00:00 +0000

Bridging Language Models and Symbolic Solvers via the Model Context Protocol

Wed, 01 Jan 2025 00:00:00 +0000

Extracting Problem Structure with LLMs for Optimized SAT Local Search

Wed, 01 Jan 2025 00:00:00 +0000

Generating Streamlining Constraints with Large Language Models

Wed, 01 Jan 2025 00:00:00 +0000

Large and Parallel Human Sorting Networks

Wed, 01 Jan 2025 00:00:00 +0000

Optimal Decision Tree Pruning Revisited: Algorithms and Complexity

Wed, 01 Jan 2025 00:00:00 +0000

SAT Modulo Symmetries: A Survey

Wed, 01 Jan 2025 00:00:00 +0000

StreamLLM: Enhancing Constraint Programming with Large Language Model-Generated Streamliners

Wed, 01 Jan 2025 00:00:00 +0000

The 3-Decomposition Conjecture: A SAT-Based Approach with Specialized Propagators

Wed, 01 Jan 2025 00:00:00 +0000

Uncovering and Verifying Optimal Community Structure in Complex Networks: A MaxSAT Approach

Wed, 01 Jan 2025 00:00:00 +0000

A General Theoretical Framework for Learning Smallest Interpretable Models

Mon, 01 Jan 2024 00:00:00 +0000

ASK-SAT: Alternating Symmetry-Breaking Combinatorial Search with SAT

Mon, 01 Jan 2024 00:00:00 +0000

Project Acronym: ASK-SAT (Alternating Symmetry-Breaking Combinatorial Search with SAT)

Funding organization: Austrian Science Fund (FWF)

Project number: P 36688

Grant DOI: 10.55776/P36688

Project Team

Topic

Many unsolved problems in discrete mathematics and extremal combinatorics can be stated as whether a combinatorial object with a particular property and size exists.

The project focuses on developing novel methods for answering such questions using the innovative Satisfiability Modulo Symmetries (SMS) technique. This approach departs from traditional exhaustive search strategies by dynamically identifying and excluding redundant sub-configurations, thus streamlining the search process while utilizing the power of solvers for the propositional satisfiability problem (SAT).

The project aims to extend the capabilities of SMS to effectively tackle the existence of objects whose defining property requires alternating quantifiers, which present unique challenges beyond the scope of conventional SAT methods. This involves integrating advanced computational tools, including quantified Boolean formulas and symmetry-reasoning technologies.

Through this research, the project aspires to advance the fields of automated reasoning and discrete mathematics.

Software

The software tool developed through the project is available via GitHub, the documentation via Read the Docs.

ASP-QRAT: A Conditionally Optimal Dual Proof System for ASP

Mon, 01 Jan 2024 00:00:00 +0000

Backdoor DNFs

Mon, 01 Jan 2024 00:00:00 +0000

Compilation and Fast Model Counting beyond CNF

Mon, 01 Jan 2024 00:00:00 +0000

Computing small Rainbow Cycle Numbers with SAT modulo Symmetries

Mon, 01 Jan 2024 00:00:00 +0000

Doctoral College Logical Methods in Computer Science

Mon, 01 Jan 2024 00:00:00 +0000

eSLIM: Circuit Minimization with SAT Based Local Improvement

Mon, 01 Jan 2024 00:00:00 +0000

Explaining Decisions in ML Models: A Parameterized Complexity Analysis

Mon, 01 Jan 2024 00:00:00 +0000

Exploiting New Types of Structure for Fixed Parameter Tractability

Mon, 01 Jan 2024 00:00:00 +0000

Funding Organisation: The Austrian Science Funds, FWF
Project Number: FWF P26696

Project Team

Eduard Eiben
Robert Ganian
Ramanujan Sridharan
Stefan Szeider (Principal Investigator)

Topic

Many important computational problems are intractable on general instances. However, realistic problem instances often contain a certain hidden structure that can be exploited to solve the problem efficiently. Such instances form a tractable class (or an island of tractability). Previous research has identified a large number of tractable classes for various NP-hard problems.

The aim of this project is to develop a rigorous framework for exploiting new kinds of structure on a wide range of problem inputs; in particular, this framework will be based on the established notion of a modulator to a tractable class of instances, which applies to problem instances that may be placed in a tractable class by a small number of local changes. The type of structure exploited by algorithms developed within the proposed research is fundamentally different from the structure exploited by known state-of-the-art approaches. This will allow us to handle natural instances where all presently known state-of-the-art approaches remain unfeasible.

Hardness of Random Reordered Encodings of Parity for Resolution and CDCL

Mon, 01 Jan 2024 00:00:00 +0000

Improved Circuit Minimization with Exact Synthesis

Mon, 01 Jan 2024 00:00:00 +0000

Learning Small Decision Trees for Data of Low Rank-Width

Mon, 01 Jan 2024 00:00:00 +0000

Learning to Solve Quantified Boolean Formulas

Mon, 01 Jan 2024 00:00:00 +0000

Funding Organisation: Vienna Science and Technology Fund, WWTF
Project Number: ICT19-060
Duration: 05/2020 - 04/2023

Project Team

Franz Xaver Reichl
Leroy Chew
Friedrich Slivovsky
Stefan Szeider

Topic

Quantified Boolean Formulas (QBFs) can succinctly encode hard problems arising in planning, verification,
and synthesis, and the development of efficient procedures for evaluating QBFs (so-called QBF solvers)
will drive advances in all of these areas.

These applications require that QBF solvers not only decide whether a formula is true or false but also
output a witnessing strategy. For instance, when using QBF to solve a program synthesis problem, we
expect solvers to return the synthesized program. Our work on solver design and proof theory has
convinced us that strategies are at the heart of QBF research. However, the prevailing theoretical models of
QBF solvers as decision procedures or proof systems do not capture the fact that they need to compute
strategies. This project aims to develop a new, richer model of QBF solvers as strategy learning algorithms.

Software

Unique: A preprocessor for (D)QBF that computes unique Skolem and Herbrand functions (GitHub).
Pedant: A certifying DQBF solver based on definition extraction (GitHub).

Parameterized Compilation

Mon, 01 Jan 2024 00:00:00 +0000

Funding Organisation: The Austrian Science Funds, FWF
Project Number: FWF P26200

Project Team

Simone Bova
Ronald de Haan
Neha Lodha
Stefan Szeider (Principal Investigator)

Topic

Knowledge compilation offers a compelling approach to coping with computationally hard problems. This line of research was initiated in the early 1990s, and since then has become a very active and progressing field. Knowledge compilation proceeds in two phases: In the first phase the input data is compiled into a new representation, which is then used in a second phase to execute a number of individual tasks efficiently. Ideally, one aims at a compilation that causes only a polynomial increase in space, and the classical theory of compilation offers theoretical tools to decide whether such a compilation is possible or not. However, systematic research shows that most relevant problems are not compilable with a polynomial increase in space. Hence, the classical theory cannot provide reasonable guarantees for these problems.

The goal of this project is to overcome this limit of classical knowledge compilation by utilizing structural aspects of problem inputs (such as as tree-likeness, degree of cyclicity, or backdoor size). As the key to this goal we propose to study knowledge compilation within the framework of parameterized complexity, which has become an important and successful research direction in algorithms and complexity. Parameterized complexity provides powerful methods and tools for exploiting structural aspects of problems and is therefore ideally suited for this purpose. Using parameters we can exploit structural aspects of the input in order to support the compilation. Hence we aim at positive results in terms of upper bounds for compilation space and compilation time for problems that are not compilable in the classical sense.

Events

Symposium on New Frontiers in Knowledge Compilation

This symposium was organised by Pierre Marquis and Stefan Szeider and held in Vienna, Austria, June 4-6, 2015. The aim of this symposium was to bring together researchers who work on knowledge compilation from various angles, including knowledge representation, constraints, theory of algorithms, complexity, machine learning, and databases, as well as researchers from related areas. Lectures and discussions have put all these different approaches into context and stimulated a fruitful exchange of ideas between researchers from different fields. The symposium had over 30 participants and featured several invited and contributed talks.

More information can be found on the symposium homepage.

Dagstuhl Seminar on Recent Trends in Knowledge Compilation

Stimulated by the success of the Symposium in Vienna, another larger meeting on this topic was organized by Adnan Darwiche (UCLA, US), Pierre Marquis (Artois University – Lens, FR), Dan Suciu (University of Washington – Seattle, US, and Stefan Szeider (TU Wien, AT). The seminar was held at Schloss Dagstuhl, Wadern, Germany, September 17-22, 2017,

The seminar had over 40 participants and featured several invited and contributed talks as well as a demo session and and open problems session.

Among others, the seminar was an excellent occasion for disseminating results of the project, in terms of several talks.

A report on the seminar has been published as Dagstuhl Report (Volume 7, Issue 9, 2018).

More information can be found on the seminar homepage.

QBF Proofs and Certificates

Mon, 01 Jan 2024 00:00:00 +0000

Funding organization: Austrian Science Fund (FWF)

Project number: (ESP 197 ESPRIT-Programm)

Grant DOI: 10.55776/ESP197

Project Team

Leroy Chew
Stefan Szeider
Friedrich Slivovsky

Topic

Quantified Boolean Formulas (QBF) extends propositional logic. Solving a QBF is theoretically more difficult than solving a propositional SAT (satisfiability) problem. QBFs are canonically PSPACE complete, meaning solving them could be used to solve any PSPACE problem by proxy. In the last decade progress in QBF solving is being undertaken. Proof complexity is the main theoretical framework used to understand SAT and QBF solving. Proof systems use the same logical rules as sound solvers, the proof size can often be a lower bound of running time between proof systems and related solvers. Proof systems can also be used to certify the correctness of solvers. However certification of QBF solvers is not yet a common occurrence.

We wish to further study the landscape of QBF proof complexity, studying the existing QBF proof systems that have emerged to capturing the solvers over the last decade. We also wish to use knowledge of soundness and complexity to make minor and major modifications to QBF proof systems, that could be beneficial to theory and practice. Our hope is that such knowledge will be of use to the QBF solving community.

QBF proof systems arranged via p-simulation

REVEAL-AI: Revealing and Utilizing the Hidden Structure for Solving Hard Problems in AI

Mon, 01 Jan 2024 00:00:00 +0000

Funding organization: Vienna Science and Technology Fund (WWTF)
Call: Information and Communication Technologies (ICT- 19)
Project number: ICT19-065 (Reveal-AI)

Project Team

Wolfgang Dvorak
Markus Hecher
Matthias König
Vaidyanathan P. R.
Anna Rapberger
André Schidler
Stefan Szeider (PI)
Stefan Woltran (co-PI)

Topic

At the core of several critical areas of AI and reasoning are hard-to-solve computational problems, such as the processing of constraints, carrying out sound reasoning tasks, and the verification of the correctness of procedures and protocols. All these problems are in general intractable and pose a challenge to algorithm design, even more as today’s applications demand more extensive problem inputs be solved. This requires new and more robust algorithms to facilitate further progress in technological innovation. Fortunately, typical problem inputs tend to contain some form of hidden structure, as the problem data is usually the product of a process. This research project is about revealing this hidden structure and utilizing it for an efficient solution.

Revisiting Causal Discovery from a Complexity-Theoretic Perspective

Mon, 01 Jan 2024 00:00:00 +0000

SAT backdoors: Depth beats size

Mon, 01 Jan 2024 00:00:00 +0000

SAT Modulo Symmetries for Graph Generation and Enumeration

Mon, 01 Jan 2024 00:00:00 +0000

SAT-based Decision Tree Learning for Large Data Sets

Mon, 01 Jan 2024 00:00:00 +0000

SAT-Based Tree Decomposition with Iterative Cascading Policy Selection

Mon, 01 Jan 2024 00:00:00 +0000

Satisfiability Modulo User Propagators

Mon, 01 Jan 2024 00:00:00 +0000

SLIM: SAT Based Local Improvement

Mon, 01 Jan 2024 00:00:00 +0000

Funding organization: Austrian Science Fund (FWF)

Project number: (FWF P 32441)

Project Team

Stefan Szeider (PI)
André Schidler
P.R. Vaidyanathan

Topic

Many problems can be efficiently translated into the propositional satisfiability problem (SAT) and then solved with a powerful SAT solver or variants such as MaxSAT or QBF-SAT. In some cases, the translation causes a significant blow-up in size, so this one-shot translation is not feasible. In this project, we overcome this limitation by repeatedly translating small local parts of the problem instance to SAT, which allows us to scale the SAT solver’s power to large instances. We could successfully implement this approach for various critical computational problems, including learning the structure of a Bayesian network, inducing an interpretable decision tree, or minimizing a Boolean circuit.

Small unsatisfiable k-CNFs with bounded literal occurrence

Mon, 01 Jan 2024 00:00:00 +0000

STRIDES: Structure Identification with SAT

Mon, 01 Jan 2024 00:00:00 +0000

Project Acronym: STRIDES (Structure Identification with SAT)

Funding organization: Austrian Science Fund (FWF)

Project number: P 36420

Grant DOI: 10.55776/P36420

Project Team

Stefan Szeider (PI)
André Schidler
P.R. Vaidyanathan
Florentina Voboril

Topic

SAT is the famous propositional satisfiability problem. It asks to assign the variables of a propositional formula with truth values 0 and 1 such that the entire formula becomes true. SAT is generally considered intractable, but over the last twenty years, computer programs (SAT solvers) have been engineered that can solve the problem surprisingly fast. Numerous other hard problems can be translated to SAT and solved via SAT solvers. However, the translation to SAT often causes a significant increase in size, which limits the application of SAT solvers to small problem inputs.

The project aims at scaling the use of SAT solvers to large problem inputs by utilizing the recently introduced SAT-based Local Improvement Method (SLIM). It starts with an initial heuristic solution and repeatedly applies a SAT solver to small local parts of the input, overcoming the size limitation. The project will investigate using SLIM for problems that ask to find a specific hard-to-find structure in given data. Such structure identification problems arise in text data, large graphs and networks, and logical circuits. It will focus on methods for making the SLIM approach more efficient and finding general insights into its workings. The research is expected to lead to new theoretical and practical results.

Structure-guided Local Improvement for Maximum Satisfiability

Mon, 01 Jan 2024 00:00:00 +0000

The Parameterized Complexity of Reasoning Problems

Mon, 01 Jan 2024 00:00:00 +0000

Reasoning, to derive conclusions from facts, is a fundamental task in Artificial Intelligence that arises in a wide range of applications from Robotics to Expert Systems. Different applications require different forms of reasoning such as Nonmonotonic Reasoning (e.g., reasoning under the presence of default as- sumptions), Constraint-Based Reasoning (reasoning with forbidden configurations), and Bayesian Reasoning (reasoning with uncertain data). All these forms of reasoning give rise to computational problems that can be solved algorithmically. The efficiency of algorithms has a direct impact on applications; for example, improved algorithms for Bayesian inference yield more accurate computer assisted medical diagnosis.

The aim of this project is to devise new efficient algorithms for reasoning problems and to gain new theoretical insights into the question of what makes a reasoning problem hard, and what makes it easy. We study reasoning problems within the framework of Parameterized Complexity, a new and rapidly emerging field of Algorithms and Complexity. Parameterized Complexity takes structural aspects of problem instances into account which are most significant for empirically observed problem-hardness. Most of the considered reasoning problems are intractable in general, but the real-world context of their origin provides structural information that can be made accessible to algorithms in form of parameters. This makes Parameterized Complexity an ideal setting for the analysis and efficient solution of these problems that we want to explore.

Two inputs for a reasoning problem: random (left) and realistic (right).

An Illustration: the picture above shows the visualizations of two inputs for a reasoning problem. The input to the left is a random input. The input to the right is a real-world input (from multiplier verification). Both inputs have approximately the same size in bits, however, evidently the real-world instance is somehow “structured”, whereas the random instance is not. The parameterized complexity approach allows to utilize this kind of structure to solve the problem efficiently.

Project Record

Project Title: The Parameterized Complexity of Reasoning Problems
Principle Investigator: Stefan Szeider
Funding Organization: European Research Council (ERC)
Project Type: ERC Starting Independent Researcher Grant
Project Volume: EUR 1.4 Mio
Project Duration: Jan 2010 - Dec 2014
Host Institution: Vienna University of Technology

Project Team

Simone Bova
Johannes Fichte
Robert Ganian
Ronald de Haan
Eva Nedoma
Friedrich Slivovsky
Stefan Szeider, project leader
Yue Chen
Serge Gaspers (University of NSW and NICTA, Australia)
Sebastian Ordyniak

de Haan, Fichte, Slivovsky, Gaspers, Ordyniak, Szeider, Bova, Ganian (from left to right)

The Power of Collaboration: Learning Large Bayesian Networks at Scale

Mon, 01 Jan 2024 00:00:00 +0000

Variable Dependencies of Quantified Boolean Formulas

Mon, 01 Jan 2024 00:00:00 +0000

Funding Organisation: The Austrian Science Fund, FWF
Project Number: FWF P 27721

Project Team

Friedrich Slivovsky
Tomas Peitl
Stefan Szeider (Professor, Principal Investigator)

Topic

The satisfiability problem of Quantified Boolean Formulas (QBF) offers succinct encodings for hard problems arising in areas such as formal verification and planning. This research project explores new ways to leverage independence of variables for QBF. The nesting of existential and universal quantifiers in Quantified Boolean Formulas can generate variable dependencies that are a serious obstacle to lifting successful techniques from propositional satisfiability to QBF. In some cases one can identify a variable dependency as spurious and conclude that the corresponding variables are in fact independent. This information can be used to significantly improve the performance of decision procedures, but deciding whether variables are independent is a highly intractable problem in itself.

The aim of this project is three-fold: (A) to advance the state of the art in detecting variable independence by developing new theory and improved algorithms for currently used methods; (B) to find new approaches to detecting and harnessing variable independence; (C) to extend the scope of successful techniques from QBF to more general problems.

Software

Research under Theme (B) has lead to the development of Qute (GitHub), a dependency learning QBF solver. Qute placed 3rd in the PCNF track and 4th in the Prenex non-CNF track of QBFEVAL'17.

The Silent (R)evolution of SAT

Thu, 01 Jun 2023 00:00:00 +0000

A SAT Solver's Opinion on the Erdős-Faber-Lovász Conjecture

Sun, 01 Jan 2023 00:00:00 +0000

Are Hitting Formulas Hard for Resolution?

Sun, 01 Jan 2023 00:00:00 +0000

Circuit Minimization with Exact Synthesis: From QBF Back to SAT

Sun, 01 Jan 2023 00:00:00 +0000

Circuit Minimization with QBF-Based Exact Synthesis

Sun, 01 Jan 2023 00:00:00 +0000

Co-Certificate Learning with SAT Modulo Symmetries

Sun, 01 Jan 2023 00:00:00 +0000

Computing optimal hypertree decompositions with SAT

Sun, 01 Jan 2023 00:00:00 +0000

Computing twin-width with SAT and branch \& bound

Sun, 01 Jan 2023 00:00:00 +0000

CSP beyond tractable constraint languages

Sun, 01 Jan 2023 00:00:00 +0000

From Data Completion to Problems on Hypercubes: A Parameterized Analysis of the Independent Set Problem

Sun, 01 Jan 2023 00:00:00 +0000

Inconsistent Cores for ASP: The Perks and Perils of Non-Monotonicity

Sun, 01 Jan 2023 00:00:00 +0000

IPASIR-UP: User Propagators for CDCL

Sun, 01 Jan 2023 00:00:00 +0000

Learning Small Decision Trees with Large Domain

Sun, 01 Jan 2023 00:00:00 +0000

On the parameterized complexity of clustering problems for incomplete data

Sun, 01 Jan 2023 00:00:00 +0000

Proven optimally-balanced Latin rectangles with SAT

Sun, 01 Jan 2023 00:00:00 +0000

SAT-Based Generation of Planar Graphs

Sun, 01 Jan 2023 00:00:00 +0000

SAT-Boosted Tabu Search for Coloring Massive Graphs

Sun, 01 Jan 2023 00:00:00 +0000

Searching for smallest universal graphs and tournaments with SAT

Sun, 01 Jan 2023 00:00:00 +0000

The Computational Complexity of Concise Hypersphere Classification

Sun, 01 Jan 2023 00:00:00 +0000

The Parameterized Complexity of Finding Concise Local Explanations

Sun, 01 Jan 2023 00:00:00 +0000

A SAT Approach to Twin-Width

Sat, 01 Jan 2022 00:00:00 +0000

A SAT Attack on Rota’s Basis Conjecture

Sat, 01 Jan 2022 00:00:00 +0000

Algorithmic Applications of Tree-Cut Width

Sat, 01 Jan 2022 00:00:00 +0000

CSP Beyond Tractable Constraint Languages

Sat, 01 Jan 2022 00:00:00 +0000

Finding a Cluster in Incomplete Data

Sat, 01 Jan 2022 00:00:00 +0000

Learning Large Bayesian Networks with Expert Constraints

Sat, 01 Jan 2022 00:00:00 +0000

Preface: 47th International Symposium on Mathematical Foundations of Computer Science, MFCS 2022, August 22-26, 2022, Vienna, Austria

Sat, 01 Jan 2022 00:00:00 +0000

Preface: Ninth workshop on graph classes, optimization, and Width Parameters, Vienna, Austria

Sat, 01 Jan 2022 00:00:00 +0000

SAT Backdoors: Depth Beats Size

Sat, 01 Jan 2022 00:00:00 +0000

Sum-of-Products with Default Values: Algorithms and Complexity Results

Sat, 01 Jan 2022 00:00:00 +0000

Threshold Treewidth and Hypertree Width

Sat, 01 Jan 2022 00:00:00 +0000

Tractable Abstract Argumentation via Backdoor-Treewidth

Sat, 01 Jan 2022 00:00:00 +0000

Weighted Model Counting with Twin-Width

Sat, 01 Jan 2022 00:00:00 +0000

Backdoor DNFs

Fri, 01 Jan 2021 00:00:00 +0000

Backdoor DNFs

Fri, 01 Jan 2021 00:00:00 +0000

Certified DQBF Solving by Definition Extraction

Fri, 01 Jan 2021 00:00:00 +0000

Certified DQBF Solving by Definition Extraction

Fri, 01 Jan 2021 00:00:00 +0000

Computing Optimal Hypertree Decompositions with SAT

Fri, 01 Jan 2021 00:00:00 +0000

Finding the Hardest Formulas for Resolution

Fri, 01 Jan 2021 00:00:00 +0000

Finding the Hardest Formulas for Resolution (Extended Abstract)

Fri, 01 Jan 2021 00:00:00 +0000

Fixed-Parameter Tractability

Fri, 01 Jan 2021 00:00:00 +0000

Fixed-Parameter Tractability

Fri, 01 Jan 2021 00:00:00 +0000

Learning fast-inference Bayesian networks

Fri, 01 Jan 2021 00:00:00 +0000

New Width Parameters for SAT and Sharp-SAT

Fri, 01 Jan 2021 00:00:00 +0000

Parameterized Complexity of Small Decision Tree Learning

Fri, 01 Jan 2021 00:00:00 +0000

Parameterized Complexity of Small Decision Tree Learning

Fri, 01 Jan 2021 00:00:00 +0000

SAT Modulo Symmetries for Graph Generation

Fri, 01 Jan 2021 00:00:00 +0000

SAT-based Decision Tree Learning for Large Data Sets

Fri, 01 Jan 2021 00:00:00 +0000

SAT-based Decision Tree Learning for Large Data Sets

Fri, 01 Jan 2021 00:00:00 +0000

The Parameterized Complexity of Clustering Incomplete Data

Fri, 01 Jan 2021 00:00:00 +0000

The Parameterized Complexity of Clustering Incomplete Data

Fri, 01 Jan 2021 00:00:00 +0000

Turbocharging Treewidth-Bounded Bayesian Network Structure Learning

Fri, 01 Jan 2021 00:00:00 +0000

A Faster Algorithm for Propositional Model Counting Parameterized by Incidence Treewidth

Wed, 01 Jan 2020 00:00:00 +0000

A Faster Algorithm for Propositional Model Counting Parameterized by Incidence Treewidth

Wed, 01 Jan 2020 00:00:00 +0000

A Time Leap Challenge for SAT-Solving

Wed, 01 Jan 2020 00:00:00 +0000

Breaking Symmetries with RootClique and LexTopsort

Wed, 01 Jan 2020 00:00:00 +0000

Breaking Symmetries with RootClique and LexTopsort

Wed, 01 Jan 2020 00:00:00 +0000

Computing Optimal Hypertree Decompositions

Wed, 01 Jan 2020 00:00:00 +0000

Computing Optimal Hypertree Decompositions

Wed, 01 Jan 2020 00:00:00 +0000

Finding the Hardest Formulas for Resolution

Wed, 01 Jan 2020 00:00:00 +0000

Finding the Hardest Formulas for Resolution

Wed, 01 Jan 2020 00:00:00 +0000

Fixed-Parameter Tractability of Dependency QBF with Structural Parameters

Wed, 01 Jan 2020 00:00:00 +0000

Fixed-Parameter Tractability of Dependency QBF with Structural Parameters

Wed, 01 Jan 2020 00:00:00 +0000

Formalizing Graph Trail Properties in Isabelle/HOL

Wed, 01 Jan 2020 00:00:00 +0000

Formalizing Graph Trail Properties in Isabelle/HOL

Wed, 01 Jan 2020 00:00:00 +0000

MaxSAT-Based Postprocessing for Treedepth

Wed, 01 Jan 2020 00:00:00 +0000

MaxSAT-Based Postprocessing for Treedepth

Wed, 01 Jan 2020 00:00:00 +0000

On Existential MSO and Its Relation to ETH

Wed, 01 Jan 2020 00:00:00 +0000

On the Parameterized Complexity of Clustering

Wed, 01 Jan 2020 00:00:00 +0000

On the Parameterized Complexity of Clustering Incomplete Data into Subspaces of Small Rank

Wed, 01 Jan 2020 00:00:00 +0000

Short Q-Resolution Proofs with Homomorphisms

Wed, 01 Jan 2020 00:00:00 +0000

Short Q-Resolution Proofs with Homomorphisms

Wed, 01 Jan 2020 00:00:00 +0000

Threshold Treewidth and Hypertree Width

Wed, 01 Jan 2020 00:00:00 +0000

Threshold Treewidth and Hypertree Width

Wed, 01 Jan 2020 00:00:00 +0000

A Join-Based Hybrid Parameter for Constraint Satisfaction

Tue, 01 Jan 2019 00:00:00 +0000

A Join-Based Hybrid Parameter for Constraint Satisfaction

Tue, 01 Jan 2019 00:00:00 +0000

A SAT Approach to Branchwidth

Tue, 01 Jan 2019 00:00:00 +0000

A SAT Approach to Branchwidth

Tue, 01 Jan 2019 00:00:00 +0000

Combining Resolution-Path Dependencies with Dependency Learning

Tue, 01 Jan 2019 00:00:00 +0000

Combining Resolution-Path Dependencies with Dependency Learning

Tue, 01 Jan 2019 00:00:00 +0000

Compendium of Parameterized Problems at Higher Levels of the Polynomial Hierarchy

Tue, 01 Jan 2019 00:00:00 +0000

Dependency Learning for QBF

Tue, 01 Jan 2019 00:00:00 +0000

Long-Distance Q-Resolution with Dependency Schemes

Tue, 01 Jan 2019 00:00:00 +0000

On the Parameterized Complexity of (k,s)-SAT

Tue, 01 Jan 2019 00:00:00 +0000

Proof Complexity of Fragments of Long-Distance Q-resolution

Tue, 01 Jan 2019 00:00:00 +0000

Proof Complexity of Fragments of Long-Distance Q-resolution

Tue, 01 Jan 2019 00:00:00 +0000

SAT-Encodings for Treecut Width and Treedepth

Tue, 01 Jan 2019 00:00:00 +0000

SAT-Encodings for Treecut Width and Treedepth

Tue, 01 Jan 2019 00:00:00 +0000

The Parameterized Complexity of Cascading Portfolio Scheduling

Tue, 01 Jan 2019 00:00:00 +0000

The Parameterized Complexity of Cascading Portfolio Scheduling

Tue, 01 Jan 2019 00:00:00 +0000

An SMT Approach to Fractional Hypertree Width

Mon, 01 Jan 2018 00:00:00 +0000

An SMT Approach to Fractional Hypertree Width

Mon, 01 Jan 2018 00:00:00 +0000

Meta-kernelization using well-structured modulators

Mon, 01 Jan 2018 00:00:00 +0000

On the Parameterized Complexity of (k,s)-SAT

Mon, 01 Jan 2018 00:00:00 +0000

Parameterized Algorithms for the Matrix Completion Problem

Mon, 01 Jan 2018 00:00:00 +0000

Polynomial-Time Validation of QCDCL Certificates

Mon, 01 Jan 2018 00:00:00 +0000

Polynomial-Time Validation of QCDCL Certificates

Mon, 01 Jan 2018 00:00:00 +0000

Portfolio Solvers for QDIMACS and QCIR

Mon, 01 Jan 2018 00:00:00 +0000

Portfolio-Based Algorithm Selection for Circuit QBFs

Mon, 01 Jan 2018 00:00:00 +0000

Portfolio-Based Algorithm Selection for Circuit QBFs

Mon, 01 Jan 2018 00:00:00 +0000

Portfolio-Based Algorithm Selection for Circuit QBFs

Mon, 01 Jan 2018 00:00:00 +0000

Solving Problems on Graphs of High Rank-Width

Mon, 01 Jan 2018 00:00:00 +0000

Sum-of-Products with Default Values: Algorithms and Complexity Results

Mon, 01 Jan 2018 00:00:00 +0000

Sum-of-Products with Default Values: Algorithms and Complexity Results

Mon, 01 Jan 2018 00:00:00 +0000

A SAT Approach to Branchwidth

Sun, 01 Jan 2017 00:00:00 +0000

Backdoor Sets for CSP

Sun, 01 Jan 2017 00:00:00 +0000

Backdoor Trees for Answer Set Programming

Sun, 01 Jan 2017 00:00:00 +0000

Backdoor Treewidth for SAT

Sun, 01 Jan 2017 00:00:00 +0000

Backdoor Treewidth for SAT

Sun, 01 Jan 2017 00:00:00 +0000

Backdoors into heterogeneous classes of SAT and CSP

Sun, 01 Jan 2017 00:00:00 +0000

Circuit Treewidth, Sentential Decision, and Query Compilation

Sun, 01 Jan 2017 00:00:00 +0000

Combining Treewidth and Backdoors for CSP

Sun, 01 Jan 2017 00:00:00 +0000

Dependency Learning for QBF

Sun, 01 Jan 2017 00:00:00 +0000

Discovering Archipelagos of Tractability for Constraint Satisfaction and Counting

Sun, 01 Jan 2017 00:00:00 +0000

Long-Distance Q-Resolution with Dependency Schemes

Sun, 01 Jan 2017 00:00:00 +0000

New Width Parameters for Model Counting

Sun, 01 Jan 2017 00:00:00 +0000

New Width Parameters for Model Counting

Sun, 01 Jan 2017 00:00:00 +0000

On the parameterized complexity of finding small unsatisfiable subsets of CNF formulas and CSP instances

Sun, 01 Jan 2017 00:00:00 +0000

On the Parameterized Complexity of Finding Small Unsatisfiable Subsets of CNF Formulas and CSP Instances

Sun, 01 Jan 2017 00:00:00 +0000

Parameterized Complexity Classes Beyond Para-NP

Sun, 01 Jan 2017 00:00:00 +0000

Rigging Nearly Acyclic Tournaments Is Fixed-Parameter Tractable

Sun, 01 Jan 2017 00:00:00 +0000

SAT-Based Local Improvement for Finding Tree Decompositions of Small Width

Sun, 01 Jan 2017 00:00:00 +0000

SAT-Based Local Improvement for Finding Tree Decompositions of Small Width

Sun, 01 Jan 2017 00:00:00 +0000

SAT-Encodings for Special Treewidth and Pathwidth

Sun, 01 Jan 2017 00:00:00 +0000

SAT-Encodings for Special Treewidth and Pathwidth

Sun, 01 Jan 2017 00:00:00 +0000

The Treewidth of Proofs

Sun, 01 Jan 2017 00:00:00 +0000

The Treewidth of Proofs

Sun, 01 Jan 2017 00:00:00 +0000

A SAT Approach to Branchwidth

Fri, 01 Jan 2016 00:00:00 +0000

Backdoors to q-Horn

Fri, 01 Jan 2016 00:00:00 +0000

Backdoors to Tractable Valued CSP

Fri, 01 Jan 2016 00:00:00 +0000

Discovering Archipelagos of Tractability for Constraint Satisfaction and Counting

Fri, 01 Jan 2016 00:00:00 +0000

Long Distance Q-Resolution with Dependency Schemes

Fri, 01 Jan 2016 00:00:00 +0000

Meta-Kernelization with Structural Parameters

Fri, 01 Jan 2016 00:00:00 +0000

Model Checking Existential Logic on Partially Ordered Sets

Fri, 01 Jan 2016 00:00:00 +0000

Model Counting for CNF Formulas of Bounded Modular Treewidth

Fri, 01 Jan 2016 00:00:00 +0000

On Existential MSO and its Relation to ETH

Fri, 01 Jan 2016 00:00:00 +0000

Parameterized Complexity Results for Agenda Safety in Judgment Aggregation

Fri, 01 Jan 2016 00:00:00 +0000

Parameterized Complexity Results for Symbolic Model Checking of Temporal Logics

Fri, 01 Jan 2016 00:00:00 +0000

Polynomial-Time Construction of Optimal MPI Derived Datatype Trees

Fri, 01 Jan 2016 00:00:00 +0000

Positive and Negative Results for Parameterized Compilability

Fri, 01 Jan 2016 00:00:00 +0000

Quantified Conjunctive Queries on Partially Ordered Sets

Fri, 01 Jan 2016 00:00:00 +0000

Quantifier reordering for QBF

Fri, 01 Jan 2016 00:00:00 +0000

Soundness of Q-resolution with dependency schemes

Fri, 01 Jan 2016 00:00:00 +0000

A complete parameterized complexity analysis of bounded planning

Thu, 01 Jan 2015 00:00:00 +0000

A SAT Approach to Clique-Width

Thu, 01 Jan 2015 00:00:00 +0000

Algorithmic Applications of Tree-Cut Width

Thu, 01 Jan 2015 00:00:00 +0000

Backdoors to Normality for Disjunctive Logic Programs

Thu, 01 Jan 2015 00:00:00 +0000

Backdoors to Tractable Answer Set Programming

Thu, 01 Jan 2015 00:00:00 +0000

Community Structure Inspired Algorithms for SAT and \#SAT

Thu, 01 Jan 2015 00:00:00 +0000

Machine Characterizations for Parameterized Complexity Classes Beyond Para-NP

Thu, 01 Jan 2015 00:00:00 +0000

Machine Characterizations for Parameterized Complexity Classes Beyond Para-NP

Thu, 01 Jan 2015 00:00:00 +0000

Meta-Kernelization using Well-Structured Modulators

Thu, 01 Jan 2015 00:00:00 +0000

On finding optimal polytrees

Thu, 01 Jan 2015 00:00:00 +0000

On the Subexponential-Time Complexity of CSP

Thu, 01 Jan 2015 00:00:00 +0000

Parameterized and subexponential-time complexity of satisfiability problems and applications

Thu, 01 Jan 2015 00:00:00 +0000

Parameterized Complexity Results for Agenda Safety in Judgment Aggregation

Thu, 01 Jan 2015 00:00:00 +0000

Parameterized Complexity Results for Symbolic Model Checking of Temporal Logics

Thu, 01 Jan 2015 00:00:00 +0000

Solving Problems on Graphs of High Rank-Width

Thu, 01 Jan 2015 00:00:00 +0000

Backdoors into Heterogeneous Classes of SAT and CSP

Wed, 01 Jan 2014 00:00:00 +0000

Compendium of Parameterized Problems at Higher Levels of the Polynomial Hierarchy

Wed, 01 Jan 2014 00:00:00 +0000

Fixed-Parameter Tractable Reductions to SAT

Wed, 01 Jan 2014 00:00:00 +0000

Guarantees and limits of preprocessing in constraint satisfaction and reasoning

Wed, 01 Jan 2014 00:00:00 +0000

Model checking existential logic on partially ordered sets

Wed, 01 Jan 2014 00:00:00 +0000

Parameterized and Subexponential-Time Complexity of Satisfiability Problems and Applications

Wed, 01 Jan 2014 00:00:00 +0000

Parameterized Complexity Results for Agenda Safety in Judgment Aggregation

Wed, 01 Jan 2014 00:00:00 +0000

Quantified Conjunctive Queries on Partially Ordered Sets

Wed, 01 Jan 2014 00:00:00 +0000

Small Unsatisfiable Subsets in Constraint Satisfaction

Wed, 01 Jan 2014 00:00:00 +0000

Subexponential Time Complexity of CSP with Global Constraints

Wed, 01 Jan 2014 00:00:00 +0000

The Parameterized Complexity of Reasoning Problems Beyond NP

Wed, 01 Jan 2014 00:00:00 +0000

Tractable answer-set programming with weight constraints: bounded treewidth is not enough

Wed, 01 Jan 2014 00:00:00 +0000

Variable Dependencies and Q-Resolution

Wed, 01 Jan 2014 00:00:00 +0000

A SAT Approach to Clique-Width

Tue, 01 Jan 2013 00:00:00 +0000

Backdoors to Abduction

Tue, 01 Jan 2013 00:00:00 +0000

Backdoors to Normality for Disjunctive Logic Programs

Tue, 01 Jan 2013 00:00:00 +0000

Backdoors to q-Horn

Tue, 01 Jan 2013 00:00:00 +0000

Capturing Structure in Hard Combinatorial Problems

Tue, 01 Jan 2013 00:00:00 +0000

Local Backbones

Tue, 01 Jan 2013 00:00:00 +0000

Meta-kernelization with Structural Parameters

Tue, 01 Jan 2013 00:00:00 +0000

Model Counting for CNF Formulas of Bounded Modular Treewidth

Tue, 01 Jan 2013 00:00:00 +0000

Model Counting for Formulas of Bounded Clique-Width

Tue, 01 Jan 2013 00:00:00 +0000

On the Subexponential Time Complexity of CSP

Tue, 01 Jan 2013 00:00:00 +0000

Parameterized Complexity and Kernel Bounds for Hard Planning Problems

Tue, 01 Jan 2013 00:00:00 +0000

Parameterized Complexity Results for Exact Bayesian Network Structure Learning

Tue, 01 Jan 2013 00:00:00 +0000

Parameterized Complexity Results for Plan Reuse

Tue, 01 Jan 2013 00:00:00 +0000

Revisiting Space in Proof Complexity: Treewidth and Pathwidth

Tue, 01 Jan 2013 00:00:00 +0000

Satisfiability of acyclic and almost acyclic CNF formulas

Tue, 01 Jan 2013 00:00:00 +0000

Strong Backdoors to Bounded Treewidth SAT

Tue, 01 Jan 2013 00:00:00 +0000

The Complexity of Repairing, Adjusting, and Aggregating of Extensions in Abstract Argumentation

Tue, 01 Jan 2013 00:00:00 +0000

The Parameterized Complexity of Constraint Satisfaction and Reasoning

Tue, 01 Jan 2013 00:00:00 +0000

Upper and Lower Bounds for Weak Backdoor Set Detection

Tue, 01 Jan 2013 00:00:00 +0000

Abstract Argumentation via Monadic Second Order Logic

Sun, 01 Jan 2012 00:00:00 +0000

Augmenting tractable fragments of abstract argumentation

Sun, 01 Jan 2012 00:00:00 +0000

Backdoors to Acyclic SAT

Sun, 01 Jan 2012 00:00:00 +0000

Backdoors to Satisfaction

Sun, 01 Jan 2012 00:00:00 +0000

Backdoors to Tractable Answer-Set Programming

Sun, 01 Jan 2012 00:00:00 +0000

Computing Resolution-Path Dependencies in Linear Time

Sun, 01 Jan 2012 00:00:00 +0000

Don't Be Strict in Local Search!

Sun, 01 Jan 2012 00:00:00 +0000

Editing graphs to satisfy degree constraints: a parameterized approach

Sun, 01 Jan 2012 00:00:00 +0000

k-Gap Interval Graphs

Sun, 01 Jan 2012 00:00:00 +0000

On Finding Optimal Polytrees

Sun, 01 Jan 2012 00:00:00 +0000

On graph contractions and induced minors

Sun, 01 Jan 2012 00:00:00 +0000

Parameterized Complexity Results for General Factors in Bipartite Graphs with an Application to Constraint Programming

Sun, 01 Jan 2012 00:00:00 +0000

Strong Backdoors to Nested Satisfiability

Sun, 01 Jan 2012 00:00:00 +0000

The Complexity of Planning Revisited - A Parameterized Analysis

Sun, 01 Jan 2012 00:00:00 +0000

A probabilistic approach to problems parameterized above or below tight bounds

Sat, 01 Jan 2011 00:00:00 +0000

Algorithms and Complexity Results for Persuasive Argumentation

Sat, 01 Jan 2011 00:00:00 +0000

Augmenting Tractable Fragments of Abstract Argumentation

Sat, 01 Jan 2011 00:00:00 +0000

Backdoors to Acyclic SAT

Sat, 01 Jan 2011 00:00:00 +0000

Backdoors to Satisfaction

Sat, 01 Jan 2011 00:00:00 +0000

Backdoors to Tractable Answer-Set Programming

Sat, 01 Jan 2011 00:00:00 +0000

Kernels for Global Constraints

Sat, 01 Jan 2011 00:00:00 +0000

Limits of Preprocessing

Sat, 01 Jan 2011 00:00:00 +0000

Monadic Second Order Logic on Graphs with Local Cardinality Constraints

Sat, 01 Jan 2011 00:00:00 +0000

On the complexity of some colorful problems parameterized by treewidth

Sat, 01 Jan 2011 00:00:00 +0000

Parameterized Proof Complexity

Sat, 01 Jan 2011 00:00:00 +0000

Satisfiability of Acyclic and almost Acyclic CNF Formulas (II)

Sat, 01 Jan 2011 00:00:00 +0000

Solving MAX-r-SAT above a tight lower bound

Sat, 01 Jan 2011 00:00:00 +0000

The parameterized complexity of k-flip local search for SAT and MAX SAT

Sat, 01 Jan 2011 00:00:00 +0000

The Parameterized Complexity of Local Consistency

Sat, 01 Jan 2011 00:00:00 +0000

Tractable cases of the extended global cardinality constraint

Sat, 01 Jan 2011 00:00:00 +0000

Algorithms and Complexity Results for Exact Bayesian Structure Learning

Fri, 01 Jan 2010 00:00:00 +0000

Algorithms and Complexity Results for Persuasive Argumentation

Fri, 01 Jan 2010 00:00:00 +0000

Algorithms for propositional model counting

Fri, 01 Jan 2010 00:00:00 +0000

Constraint satisfaction with bounded treewidth revisited

Fri, 01 Jan 2010 00:00:00 +0000

On Contracting Graphs to Fixed Pattern Graphs

Fri, 01 Jan 2010 00:00:00 +0000

Parameterized Complexity Results for General Factors in Bipartite Graphs with an Application to Constraint Programming

Fri, 01 Jan 2010 00:00:00 +0000

Reasoning in Argumentation Frameworks of Bounded Clique-Width

Fri, 01 Jan 2010 00:00:00 +0000

Satisfiability of Acyclic and Almost Acyclic CNF Formulas

Fri, 01 Jan 2010 00:00:00 +0000

Solving MAX-r-SAT Above a Tight Lower Bound

Fri, 01 Jan 2010 00:00:00 +0000

Tractable Answer-Set Programming with Weight Constraints: Bounded Treewidth Is not Enough

Fri, 01 Jan 2010 00:00:00 +0000

A Probabilistic Approach to Problems Parameterized above or below Tight Bounds

Thu, 01 Jan 2009 00:00:00 +0000

Backdoor sets of quantified Boolean formulas

Thu, 01 Jan 2009 00:00:00 +0000

Clique-width is NP-complete

Thu, 01 Jan 2009 00:00:00 +0000

Covering graphs with few complete bipartite subgraphs

Thu, 01 Jan 2009 00:00:00 +0000

Matched Formulas and Backdoor Sets

Thu, 01 Jan 2009 00:00:00 +0000

The Parameterized Complexity of k-Flip Local Search for SAT and MAX SAT

Thu, 01 Jan 2009 00:00:00 +0000

Backdoor Trees

Tue, 01 Jan 2008 00:00:00 +0000

Fixed-parameter algorithms for artificial intelligence, constraint satisfaction, and database problems

Tue, 01 Jan 2008 00:00:00 +0000

Fixed-parameter complexity of minimum profile problems

Tue, 01 Jan 2008 00:00:00 +0000

Monadic Second Order Logic on Graphs with Local Cardinality Constraints

Tue, 01 Jan 2008 00:00:00 +0000

Not So Easy Problems For Tree Decomposable Graphs (invited talk)

Tue, 01 Jan 2008 00:00:00 +0000

Parameterized Graph Editing with Chosen Vertex Degrees

Tue, 01 Jan 2008 00:00:00 +0000

Parameterized SAT

Tue, 01 Jan 2008 00:00:00 +0000

The Parameterized Complexity of Regular Subgraph Problems and Generalizations

Tue, 01 Jan 2008 00:00:00 +0000

Tractable Cases of the Extended Global Cardinality Constraint

Tue, 01 Jan 2008 00:00:00 +0000

Algorithms for Propositional Model Counting

Mon, 01 Jan 2007 00:00:00 +0000

Backdoor Sets of Quantified Boolean Formulas

Mon, 01 Jan 2007 00:00:00 +0000

Covering Graphs with Few Complete Bipartite Subgraphs

Mon, 01 Jan 2007 00:00:00 +0000

Matched Formulas and Backdoor Sets

Mon, 01 Jan 2007 00:00:00 +0000

On the Complexity of Some Colorful Problems Parameterized by Treewidth

Mon, 01 Jan 2007 00:00:00 +0000

Parameterized Proof Complexity

Mon, 01 Jan 2007 00:00:00 +0000

Solving \#SAT using Vertex Covers

Mon, 01 Jan 2007 00:00:00 +0000

The Linear Arrangement Problem Parameterized Above Guaranteed Value

Mon, 01 Jan 2007 00:00:00 +0000

Without Loss of Generality - Symmetric Reasoning for Resolution Systems (Invited Talk)

Mon, 01 Jan 2007 00:00:00 +0000

A note on unsatisfiable k-CNF formulas with few occurrences per variable

Sun, 01 Jan 2006 00:00:00 +0000

Clique-width Minimization is NP-hard

Sun, 01 Jan 2006 00:00:00 +0000

Constraint satisfaction with bounded treewidth revisited

Sun, 01 Jan 2006 00:00:00 +0000

Fixed-Parameter Complexity of Minimum Profile Problems

Sun, 01 Jan 2006 00:00:00 +0000

On Finding Short Resolution Refutations and Small Unsatisfiable Subsets

Sun, 01 Jan 2006 00:00:00 +0000

Solving \#SAT using Vertex Covers

Sun, 01 Jan 2006 00:00:00 +0000

The Linear Arrangement Problem Parameterized Above Guaranteed Value

Sun, 01 Jan 2006 00:00:00 +0000

Backdoor Sets for DLL Subsolvers

Sat, 01 Jan 2005 00:00:00 +0000

Computing unsatisfiable k-SAT instances with few occurrences per variable

Sat, 01 Jan 2005 00:00:00 +0000

Generalizations of matched CNF formulas

Sat, 01 Jan 2005 00:00:00 +0000

On Edge-Colored Graphs Covered by Properly Colored Cycles

Sat, 01 Jan 2005 00:00:00 +0000

The Complexity of Resolution with Generalized Symmetry Rules

Sat, 01 Jan 2005 00:00:00 +0000

Computing Unsatisfiable k-SAT Instances with Few Occurrences per Variable

Thu, 01 Jan 2004 00:00:00 +0000

Detecting Backdoor Sets with Respect to Horn and Binary Clauses

Thu, 01 Jan 2004 00:00:00 +0000

Minimal unsatisfiable formulas with bounded clause-variable difference are fixed-parameter tractable

Thu, 01 Jan 2004 00:00:00 +0000

On Finding Short Resolution Refutations and Small Unsatisfiable Subsets

Thu, 01 Jan 2004 00:00:00 +0000

On fixed-parameter tractable parameterizations of SAT

Thu, 01 Jan 2004 00:00:00 +0000

On Theorems Equivalent with Kotzig's Result on Graphs with Unique 1-Factors

Thu, 01 Jan 2004 00:00:00 +0000

The Parameterized Complexity of SAT Backdoors

Thu, 01 Jan 2004 00:00:00 +0000

Finding paths in graphs avoiding forbidden transitions

Wed, 01 Jan 2003 00:00:00 +0000

Homomorphisms of Conjunctive Normal Forms

Wed, 01 Jan 2003 00:00:00 +0000

Minimal unsatisfiable formulas with bounded clause-variable difference are fixed-parameter tractable

Wed, 01 Jan 2003 00:00:00 +0000

Minimal unsatisfiable formulas with bounded clause-variable difference are fixed-parameter tractable

Wed, 01 Jan 2003 00:00:00 +0000

The complexity of resolution with generalized symmetry rules

Wed, 01 Jan 2003 00:00:00 +0000

Generalizations of matched CNF formulas

Tue, 01 Jan 2002 00:00:00 +0000

Polynomial-time recognition of minimal unsatisfiable formulas with fixed clause-variable difference

Tue, 01 Jan 2002 00:00:00 +0000

Conjunctive Normal Forms with Bounded Deficiency

Mon, 01 Jan 2001 00:00:00 +0000

NP-Completeness of Refutability by Literal-Once Resolution

Mon, 01 Jan 2001 00:00:00 +0000