Lista referatów

• 2020-12-02, godz. 14:15, online

  Bartek Klin (MIM UW)

  Nondeterministic and co-nondeterministic implies deterministic, for data languages.

  I will explain why, if a data language and its complement are both recognized by non-deterministic register automata (without guessing), then they are both recognized by deterministic ones. The proof relies on the technology of sets with atoms. This is joint work with Sławek Lasota and Szymon Toru...

• 2020-11-25, godz. 14:15, online

  Corentin Barloy (University of Lille)

  Bidimensional linear recursive sequences and universality of unambiguous register automata

  We study the universality and inclusion problems for register automata over equality data (A, =). We show that the universality and inclusion problems can be solved with 2-EXPTIME complexity when both automata are without guessing and unambiguous, improving on the currently best-known 2-EXPSPACE upp...

• 2020-11-18, godz. 14:15, online

  Janusz Schmude (MIM UW)

  Polynomial grammars with substitution

  Polynomial grammars are grammars whose nonterminals generate tuples of integers (or elements of some ring in general) and productions use polynomial functions. They proved to be useful for proving decidability of equivalence of MSO transductions over strings and unordered trees and in general can be...

• 2020-11-04, godz. 14:15, Online

  Mikołaj Bojańczyk (MIM UW)

  Regular expressions for data words

  I will discuss a proposal (one of many others) for regular expressions that use infinite alphabets. The regular expressions describe exactly the languages that can be recognised by nondeterministic orbit-finite automata (equivalently, nondeterministic register automata). The basic idea is to conside...

• 2020-10-21, godz. 14:15, online

  Szymon Toruńczyk (Uniwersytet Warszawski (MIMUW))

  A model-theoretic characterization of bounded twin-width

  Twin-width is a graph parameter introduced recently in a series of papers by Bonnet, Geniet, Kim, Thomassé, and Watrigant. Among others, classes of bounded twin-width include all proper minor-closed classes, all classes of bounded tree-width or rank-width. We give a model-theoretic characterizat...

• 2020-10-14, godz. 14:00, online

  Colin Geniet (ENS Paris-Saclay)

  Twin-Width of Graphs

  Twin-width is a graph complexity measure based on a notion of width of permutations by Guillemot and Marx [SODA '14]. Twin-width is defined through sequences of d-contractions, which witness that the twin-width is at most d. Notable classes of graphs with bounded twin-width are proper minor-close...

• 2020-06-24, godz. 14:15, 5050

  Pierre Pradic (ENS Lyon)

  Implicit automata in λ-calculi (joint work with Lê Thành Dũng (a.k.a. Tito) Nguyễn)

  This work is part of an exploration of the expressiveness of the simply-typed λ-calculus (STLC) and related substructural variants (linear, affine, planar) using Church encodings of datatypes. More specifically, we are interested in the connection with automata theory for string trans...

• 2020-06-17, godz. 14:15, 5050

  Jakub Gajarsky (Uniwersytet Warszawski)

  Differential games for FO logic

  I will introduce differential games for FO logic of graphs, a new variant of Ehrenfeucht-Fraisse games. These games are an attempt to extend currently used locality-based techniques for FO logic in a way which works naturally on non-sparse graphs. The hope is that the underlying idea can lea...

• 2020-06-10, godz. 14:15, Online seminar

  Nathanael Fijalkow (CNRS, LaBRI)

  Learning Probabilistic Context-Free Grammar

  In this talk I will report on a joint work with Alexander Clark about learning (a subclass of) probabilistic context-free grammars published in the Transactions of the Association for Computational Linguistics. The objective of the talk is to introduce the main tool: matrix factorisation. ...

• 2020-06-03, godz. 14:15, Online seminar

  Julian Salamanca (Uniwersytet Warszawski)

  Lattices do not distribute over powerset

  I will show that there is no distributive law of the free lattice monad over the powerset monad. The proof presented also works for other classes of lattices such as (bounded) distributive/modular lattices and also for some variants of the powerset monad such as the (nonempty) finite powerse...

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