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FraSMT - A tool for computing the fractional hypertree width of hypergraphs

Bounded fractional hypertree width (fhtw) is the most general known structural property that guarantees polynomial-time solvability of the constraint satisfaction problem. Bounded fhtw generalizes other structural properties like bounded induced width and bounded hypertree width.

FraSMT is the first practical algorithm for computing the fhtw and its associated structural decomposition. FraSMT is based on an efficient encoding of the decomposition problem to SMT (SAT modulo Theory) with Linear Arithmetic as implemented in the SMT solver Z3. The encoding is further strengthened by preprocessing and symmetry breaking methods.

Downloads

The fraSMT tool can be downloaded from this GitHub page.

Benchmark instances can be downloaded from this Zendodo.org page.

Team

Markus Hecher, Johannes Fichte, Neha Lodha, Stefan Szeider

Publications

1 result
2018
[1]An SMT Approach to Fractional Hypertree Width
Johannes K. Fichte, Markus Hecher, Neha Lodha, Stefan Szeider
Proceedings of CP 2018, the 24rd International Conference on Principles and Practice of Constraint Programming (John N. Hooker, ed.), volume 11008 of Lecture Notes in Computer Science, pages 109–127, 2018, Springer Verlag.
[bibtex] [pdf] [doi]

News

  • Best Paper Award at SOFSEM 2025

    Best Paper Award at SOFSEM 2025

    2025-01-23
    Thomas Depian, Simon D. Fink, Alexander Firbas, Robert Ganian, and Martin Nöllenburg received the Best Paper Award for their paper …Read More »
  • Markus Wallinger receives Award of Excellence for his PhD Thesis

    Markus Wallinger receives Award of Excellence for his PhD Thesis

    2024-12-05
    Our former group member Markus Wallinger won the Award of Excellence by the Federal Ministry for Education, Science and Research. …Read More »
  • Thomas Depian receives State Prize for his Master’s Thesis

    Thomas Depian receives State Prize for his Master’s Thesis

    2024-11-21
    Our group member Thomas Depian won the Appreciation Award given by the Federal Ministry for Education, Science and Research. This …Read More »
  • Best Paper Award at GECCO 2024 for M. Bresich, G. Raidl, and S. Limmer

    Best Paper Award at GECCO 2024 for M. Bresich, G. Raidl, and S. Limmer

    2024-07-24
    Maria Bresich, Günther Raidl, and Steffen Limmer received the best paper award at the 2024 Genetic and Evolutionary Computation Conference …Read More »
  • Welcome to our Feodor Lynen Fellow Dr. Frank Sommer

    Welcome to our Feodor Lynen Fellow Dr. Frank Sommer

    2024-06-14
    On June 1, 2024, Dr. Frank Sommer has joined the Algorithms and Complexity group with a prestigious Feodor Lynen postdoc …Read More »

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