Organizers

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

Information

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

Research fields

List of talks

Oct. 10, 2012, 2:15 p.m.
Bartek Klin (Uniwersytet Warszawski)
in nominal sets (P!=NP)
After a brief recap on nominal sets, and following a standard definition of deterministic and nondeterministic Turing machines, I will show a nominal language that is in NP, but is not deterministically recognizable by a …
Oct. 3, 2012, 2:15 p.m.
Mikołaj Bojańczyk (Uniwersytet Warszawski)
Automating automata exams
Online education is hot. One weakness is grading students' solutions to problems. So far, automatic systems can do superficial grading of genuine problems (e.g. multiple choice questions about theory, or testing algorithms), or genuine grading …
July 18, 2012, 2:15 p.m.
Marcin Przybyłko (Uniwersytet Warszawski)
Between tree patterns and conjunctive queries: computational complexity of boolean combinations of patterns.
In static analysis of patterns, negation causes drastic increase of complexity. When consider patterns that allow both data comparison and negation, undecidability can be reached with simple queries. Even without data, potential complexity is unacceptably …
June 28, 2012, 2:15 p.m.
Wojciech Kazana (INRIA and ENS Cachan)
joint work with Luc Segoufin (First-order logic over classes of graphs with bounded expansion)
In 2010 it has been shown by Dvorak, Kral and Thomas that the model-checking problem for first-order logic over classes of graphs with bounded expansion can be solved in linear time. In this talk I …
June 20, 2012, 2:15 p.m.
Nathanaël Fijalkow (Uniwersytet Warszawski)
joint work with Martin Zimmermann (Cost-Parity Games)
The starting point of this work is the following observation: although similar in flavor, parity games and finitary parity games are very different from an algorithmic perspective. Both are two-player games on graphs whose vertices …
June 13, 2012, 2:15 p.m.
Szczepan Hummel (Uniwersytet Warszawski)
Unambiguous Tree Languages Are Topologically Harder Than Deterministic Ones
Topological complexity becomes more and more popular set complexity measure in automata theory. One of its remarkable uses is the separation of the classes of languages.I will address the question of the topological complexity of …
June 13, 2012, 1:15 p.m.
Violeta Manevska (St. Clement of Ohrid University of Bitola, Macedonia)
Generalization of the Theory of Finite Semigroup Automata
Observing the automata, we can see that they, during their work, make a transition from one state to another, on which a word from an alphabet corresponds, and in the end they finish in some …
June 6, 2012, 2:15 p.m.
Szymon Toruńczyk (Uniwersytet Warszawski)
joint work with Mikołaj Bojańczyk, Bartek Klin, Sławek Lasota (Imperative programming with FM-sets)
I will describe a rather natural programming language for working with orbit-finite Fraenkel-Mostowski sets (aka "nominal" sets).
May 30, 2012, 2:15 p.m.
Mikołaj Bojańczyk (Uniwersytet Warszawski)
joint work with Vince Barany, Diego Figueira, Paweł Parys (Which data words are simple from an XPath perspective?)
XPath satisfiability is undecidable. However, when doing the undecidability proof, one produces formulas that are only satisfied by very artificial data words. We propose a measure of data words, emulating tree-width for graphs, such that …
May 23, 2012, 2:15 p.m.
Tony Tan (University of Edinburgh)
An Automata Model for Trees with Ordered Data Values
Data trees are trees in which each node, besides carrying a label from a finite alphabet,also carries a data value from an infinite domain.They have been used as an abstraction model for reasoning tasks on …
May 16, 2012, 2:15 p.m.
Artur Jeż (Uniwersytet Wrocławski)
Recompression-based PSPACE algorithm for word equations.
In this talk I will present an application of a simple technique of local recompression, to word equations. The technique is based on iterative replacement of pairs of letters appearing in the equation by a …
May 9, 2012, 2:15 p.m.
Nathanael Fijalkow (joint work with Hugo Gimbert and Youssouf Oualhadj) (Uniwersytet Warszawski)
Deciding the value 1 problem for probabilistic leaktight automata
In this talk, I will present some recent work on the value 1 problem for probabilistic automata over finite words: given a probabilistic automaton, are there words accepted with probability arbitrarily close to 1?This problem …
April 25, 2012, 2:15 p.m.
Igor Walukiewicz (LaBRI, Bordeaux)
Verification on higher-order recursive schemes
We propose a new approach to analysing higher-order recursive schemes. Higher-order recursive schemes were introduced by Damm in the 80-ties as a respelling of simply-typed lambda calculus with fixpoints (lambda-Y). In this century the interest …
April 18, 2012, 2:15 p.m.
Anca Muscholl (LaBRI, Bordeaux)
joint work with B. Genest, H. Gimbert and I. Walukiewicz (Asynchronous games over tree architectures)
The control problem starts with a plant and asks to restrict its controllable actions in such a way that a given specification is met. The synthesis problem can be seen as a special case of …
April 4, 2012, 2:15 p.m.
Paweł Parys (Uniwersytet Warszawski)
Collapsible Pushdown Systems
I will briefly describe two results (the second one is a joint work with A. Kartzow). One is that collapsible pushdown systems are more expressible that higher-order pushdown systems without collapse, for any level. This …