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Wydział Matematyki, Informatyki i Mechaniki Uniwersytetu Warszawskiego

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Seminarium „Teoria automatów”

Cotygodniowe seminarium badawcze

Lista referatów

  • 2022-10-26, godz. 14:15, 5050

    Michael Blondin (Université de Sherbrooke)

    Separators in continuous Petri nets

    In this talk, we will consider Petri nets: a well-established formalism for the analysis of concurrent systems. Testing whether a target Petri net configuration cannot be reached often amounts to proving the absence of bugs in a system. Thus, formally certifying unreachability is practically (an...

  • 2022-10-19, godz. 14:15, 5050

    Szymon Toruńczyk (MIM UW)

    On monadically stable and monadically NIP classes of graphs

    Sparsity theory, initiated by Ossona de Mendez and Nesetril, identifies those classes of sparse graphs that are tractable in various ways (e.g. from the perspective of the model checking problem for first order logic) as exactly the nowhere dense classes. There is an ongoing effort aimed at gene...

  • 2022-10-11, godz. 14:15, 5820

    Stefan Göller (Universität Kassel)

    The AC0-complexity of visibly pushdown languages.

    The talk will be on the question which visibly pushdown languages (VPLs) are in the complexity class AC0. We provide a conjectural characterization that isolates a stubborn subclass of very particular one-turn visibly pushdown languages (that we call intermediate VPLs) any of which our community ...

  • 2022-10-05, godz. 14:15, 5050

    Nguyễn Lê Thành Dũng (École normale supérieure de Lyon)

    A transducer model for simply typed λ-definable functions

    Among the natural ways to define functions ℕ^k -> ℕ in the simply typed λ-calculus, one of them allows hyperexponential growth (any tower of exponentials) but excludes many basic functions such as subtraction and equality, as was discovered by Statman in the 1980s. Until now, this function clas...

  • 2022-06-15, godz. 14:15, 5050

    Albert Gutowski (MIM UW)

    Finite entailment of UCRPQs over ALC ontologies

    We solve finite ontology-mediated query entailment for ontologies expressed in ALC (a description logic, closely related to (multi)modal logic) and queries expressed as UCRPQs (extending UCQs - unions of conjunctive queries - with constraints on paths given by regular expressions). We combine a sim...

  • 2022-06-08, godz. 14:15, 5050

    Jędrzej Kołodziejski (MIM UW)

    Multi-valued Fixpoint Logic

    We investigate multi-valued fixpoint logic, an extension of the classical mu-calculus where logical values range over a fixed complete lattice A equipped with monotone operations as connectives. We present equivalent game semantics for the logic and use it to investigate the case when A is the unit...

  • 2022-06-01, godz. 14:15, 5050

    Michał Skrzypczak (MIM UW)

    Computing measures of regular languages via fixpoint expressions

    During the talk I will present our ongoing work with Damian Niwiński and Paweł Parys on computing measures of regular languages. Our approach (following earlier results with Marcin Przybyłko) is to reduce the problem to certain fixpoint expression evaluated in a specific ordered set (called Proba...

  • 2022-05-25, godz. 14:15, 5050

    Olivier Carton; Sebastian Maneth (University of Paris; University of Bremen)

    Tight links between normality and automata; Two Applications of the Parikh Property

    Abstract (Tight links between normality and automata): Normality has been introduced by É. Borel more than one hundred years ago. A real number is normal to an integer base if, in its infinite expansion expressed in that base, all blocks of digits of the same length have the same limiting frequenc...

  • 2022-05-11, godz. 14:15, 5050

    Filip Mazowiecki (MIM UW)

    The complexity of soundness in workflow nets

    Workflow nets are a popular variant of Petri nets that allow for algorithmic formal analysis of business processes. The central decision problems concerning workflow nets deal with soundness, where the initial and final configurations are specified. Intuitively, soundness states that from every reac...

  • 2022-04-27, godz. 14:15, 5050

    David Purser (MIM UW)

    The Skolem Problem for Simple Linear Recurrence Sequences

    The Skolem Problem, asks to decide whether a linear recurrence sequence has a zero term. The Skolem-Mahler-Lech theorem states that the set of zeros of a linear recurrence sequence is the union of a finite set and finitely many arithmetic progressions. Although the result is almost 90 years old, the...