Cotygodniowe seminarium badawcze
Organizatorzy
- prof. dr hab. Mikołaj Bojańczyk
- prof. dr hab. Damian Niwiński
Informacje
środy, 14:15 , sala: 5050Dziedziny badań
Lista referatów
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9 października 2024 14:15
Lorenzo Clemente (University of Warsaw)
Control theory and series in noncommuting variables (Control theory and series in noncommuting variables)
We present Michel Fliess' work from the 1970's showing surprising connections between control theory and the theory of series in noncommuting variables. More precisely, to a dynamical system with inputs S one can associate a …
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2 października 2024 14:15
Ioannis Eleftheriadis (University of Cambridge)
Preservation theorems on tame classes of finite structures (Preservation theorems on tame classes of finite structures)
Preservation theorems provide a correspondence between the syntactic structure and the semantic behaviour of first-order sentences. The study of preservation theorems relativised to classes of finite structures was initiated by Atserias, Dawar, and Kolaitis [JACM, …
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4 września 2024 14:15
Sven Manthe (University of Bonn)
The Borel monadic theory of order is decidable (The Borel monadic theory of order is decidable)
When proving decidability of S2S, Rabin derived decidability of the monadic theory of (ℝ,<) with quantification restricted to Fσ-sets. Undecidability of the unrestricted monadic theory of (ℝ,<) was proven by Shelah. We discuss decidability for …
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19 czerwca 2024 14:15
Teodor Knapik (ISEA, Université de la Nouvelle Calédonie)
Lindenmayer graph languages, first-order theories and expanders (Lindenmayer graph languages, first-order theories and expanders)
Imagined by Kolmogorov in the middle of past century, expanders form remarkable graph families with applications in areas as diverse as robust communication networks and probabilistically checkable proofs, to name just two. Since the proof …
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12 czerwca 2024 14:15
Łukasz Kamiński (University of Warsaw)
Bi-reachability in Petri nets with data
Petri nets with equality data is an extension of plain Petri nets where tokens carry values from an infinite data domain, and executability of transitions is conditioned by equalities between data values. The most fundamental …
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5 czerwca 2024 14:15
Vincent Michielini (University of Warsaw)
A new characterisation for FO2 over finite words
First-Order Logic with two variables, over finite words, is known for having many semantic characterisations: turtle languages, unambiguous monomials, deterministic partially ordered 2-way automata... In this talk, we will focus on the second one: a …
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29 maja 2024 14:15
Filip Mazowiecki (University of Warsaw)
Determinisation and Unambiguisation of Polynomially-Ambiguous Rational Weighted Automata
We study the determinisation and unambiguisation problems of weighted automata over the rational field: given a weighted automaton, can we determine whether there exists an equivalent deterministic, respectively unambiguous, weighted automaton? Recent results by Bell …
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22 maja 2024 14:15
Jakub Kozik (Jagiellonian University)
Choosability version of Thue's theorem on nonrepetitive sequences
Pattern avoidance is a deeply studied problem within the field of combinatorics on words. One of the seminal results of this area is the theorem of Thue which asserts that there exists an infinite word …
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15 maja 2024 14:15
Igor Walukiewicz (CNRS, LaBRI, Bordeaux University)
Rethinking Partial-Order Methods
The goal of partial-order methods is to speed up explicit state exploration of concurrent systems. The state space of these systems grows exponentially with the number of components. Yet, explicit state exploration remains one of …
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24 kwietnia 2024 14:15
Gorav Jindal (Max Planck Institute for Software Systems)
Sign Me Up: PosSLP, Sign Testing, and Polynomials
Given an integer, deciding its positivity may appear trivial initially. However, this problem becomes more compelling when the integer is presented in a compact form, as opposed to being explicitly represented as a bit string. …
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17 kwietnia 2024 14:15
Shuo Pang (University of Copenhagen)
Supercritical and Robust Trade-offs for Resolution Depth Versus Width and Weisfeiler–Leman
We give the first robust resolution trade-offs for which low width implies depth superlinear in the formula size. We show analogous results for the Weisfeiler–Leman algorithm, which also translate into trade-offs between number of variables …
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10 kwietnia 2024 14:15
Clotilde Biziere (University of Warsaw / ENS Paris)
Reachability in 2-dimensional Branching Vector Addition Systems with States
Vector addition systems with states (VASS) are finite-state machines equipped with a finite number of counters ranging over nonnegative integers. Operations on counters are limited to incrementation and decrementation. Their central algorithmic problem is reachability: …
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27 marca 2024 14:15
Tim Seppelt (RWTH Aachen University)
Homomorphism Indistinguishability: Characterisations, Closure, Complexity
In 1967, Lovász proved that two graphs G and H are isomorphic iff they are homomorphism indistinguishable over the the family of all graphs, i.e. for all graphs F the number of homomorphisms from F …
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20 marca 2024 14:15
Jingjie Yang (University of Oxford)
Niezmiennicze podprzestrzenie przestrzeni liniowych orbitowo skończonego wymiaru (Equivariant subspaces of orbit-finite-dimensional vector spaces)
In their LICS21 paper, Bojańczyk, Klin, and Moerman gave an equivalence algorithm for weighted orbit-finite automata: they construct a chain of configuration spaces that are closed under both linear combinations and atom permutations; crucially, termination …