Organizers

prof. dr hab. Mikołaj Bojańczyk
prof. dr hab. Damian Niwiński

Information

Wednesdays, 2:15 p.m. , room: 5440

Research fields

List of talks

Dec. 14, 2022, 2:15 p.m.
Antonio Casares Santos (LaBRI, Université de Bordeaux)
A correspondence between memory and automata for Muller languages
In this talk, we will be interested in infinite-duration games using Muller winning conditions, that is, the objective of such games is given by a boolean combination of colors that have to appear infinitely often. …
Dec. 7, 2022, 2:15 p.m.
Lorenzo Clemente (MIM UW)
Decidability of equivalence of deterministic one-way multitape finite automata
I will present an old decidability result by Harju and Karhumäki, as in the title. The original proof involves some very nice algebraic constructions, which constitute the motivation for this presentation. We start from the …
Nov. 30, 2022, 2:15 p.m.
David Purser (MIM UW)
The big-O problem for max-plus automata
Given two weighted automata A and B over the (N, max, plus) semi-ring we consider the problem of deciding whether there exists a constant c such that A(w) ≤ c B(w) + c for every …
Nov. 23, 2022, 2:15 p.m.
Jakob Piribauer (TU Dresden)
Tradeoff between expectation and variance in Markov decision processes
The stochastic shortest path problem asks to resolve the non-deterministic choices in a Markov decision process (MDP) such that the expected accumulated weight before reaching a target state is maximized. This problem is well-studied and …
Nov. 16, 2022, 2:15 p.m.
Mikołaj Bojańczyk (MIM UW)
Folding interpretations
In this talk, I will discuss a characterisation of the polyregular functions which uses folding. The idea is to use the combinator approach, i.e. start with certain atomic functions (such as list concatenation) and apply …
Nov. 9, 2022, 2:15 p.m.
Paweł Parys (MIM UW)
Weak Bisimulation Finiteness of Pushdown Systems With Deterministic ε-Transitions Is 2-EXPTIME-Complete
We consider the problem of deciding whether a given pushdown system all of whose ε-transitions are deterministic is weakly bisimulation finite, that is, whether it is weakly bisimulation equivalent to a finite system. We prove …
Oct. 26, 2022, 2:15 p.m.
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 …
Oct. 19, 2022, 2:15 p.m.
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 …
Oct. 11, 2022, 2:15 p.m.
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 …
Oct. 5, 2022, 2:15 p.m.
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, …
June 15, 2022, 2:15 p.m.
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 …
June 8, 2022, 2:15 p.m.
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 …
June 1, 2022, 2:15 p.m.
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 …
May 25, 2022, 2:15 p.m.
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 …
May 11, 2022, 2:15 p.m.
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 …