5 results
Mikołaj Bojańczyk ; Bartek Klin ; Sławomir Lasota.
We study languages over infinite alphabets equipped with some structure that can be tested by recognizing automata. We develop a framework for studying such alphabets and the ensuing automata theory, where the key role is played by an automorphism group of the alphabet. In the process, we generalize […]
Published on August 15, 2014
Mikolaj Bojanczyk ; Luc Segoufin.
We study tree languages that can be defined in \Delta_2 . These are tree languages definable by a first-order formula whose quantifier prefix is forall exists, and simultaneously by a first-order formula whose quantifier prefix is . For the quantifier free part we consider two signatures, either the […]
Published on October 20, 2010
Mikołaj Bojańczyk ; Thomas Colcombet.
We define a new class of languages of $\omega$-words, strictly extending $\omega$-regular languages. One way to present this new class is by a type of regular expressions. The new expressions are an extension of $\omega$-regular expressions where two new variants of the Kleene star $L^*$ are […]
Published on October 26, 2017
Mikołaj Bojańczyk ; Martin Grohe ; Michał Pilipczuk.
We prove that for every positive integer k, there exists an MSO_1-transduction that given a graph of linear cliquewidth at most k outputs, nondeterministically, some cliquewidth decomposition of the graph of width bounded by a function of k. A direct corollary of this result is the equivalence of […]
Published on January 25, 2021
Mikołaj Bojańczyk ; Michał Pilipczuk.
The classic algorithm of Bodlaender and Kloks [J. Algorithms, 1996] solves the following problem in linear fixed-parameter time: given a tree decomposition of a graph of (possibly suboptimal) width k, compute an optimum-width tree decomposition of the graph. In this work, we prove that this problem […]
Published on February 3, 2022