Organizatorzy

dr hab. Michał Pilipczuk, prof. ucz.

Informacje

piątki, 14:15 , sala: 5060

Strona domowa

https://students.mimuw.edu.pl/~kd417818/algorithms-seminar/

Dziedziny badań

Algorytmika

Lista referatów

8 października 2020 12:15
Wiktor Zuba
The number of repetitions in 2D-strings
The notions of periodicity and repetitions in strings, and hence these of runs and squares, naturally extend to two-dimensional strings. We consider two types of repetitions in 2D-strings: 2D-runs and quartics (quartics are a 2D-version …
4 czerwca 2020 12:15
Kunal Dutta (University of Warsaw)
Dimensionality Reduction for k-distance Applied to Persistent Homology
Given a set P of n points and a constant k, we are interested in computing the persistent homology of the Čech filtration of P for the k-distance, and investigate the effectiveness of dimensionality reduction …
26 marca 2020 12:15
Michał Pilipczuk (University of Warsaw)
Quasi-polynomial time approximation schemes for the Maximum Weight Independent Set Problem in H-free graphs
This Thursday we will have our first virtual algorithms seminar! Please join us at https://us04web.zoom.us/j/967084831 (Meeting ID: 967 084 831). In the Maximum Independent Set problem we are asked to find a set of pairwise …
16 stycznia 2020 12:15
Kunal Dutta (MIM UW)
Randomized Incremental Construction of Delaunay Triangulations of Nice Point Sets
Randomized incremental construction (RIC) is one of the most important paradigms for building geometric data structures. Clarkson and Shor developed a general theory that led to numerous algorithms that are both simple and efficient in …
9 stycznia 2020 12:15
Panagiotis Charalampopoulos (King's College London and University of Warsaw)
Almost Optimal Distance Oracles for Planar Graphs
We present new tradeoffs between space and query-time for exact distance oracles in directed weighted planar graphs. These tradeoffs are almost optimal in the sense that they are within polylogarithmic, subpolynomial or arbitrarily small polynomial factors …
19 grudnia 2019 12:15
Jakub Łącki (Google Research NY)
Massively parallel algorithms for finding connected components
In this talk we consider the problem of finding connected components in a distributed setting. We present state of the art algorithms that achieve near-optimal round complexity and work well in practice. Our main focus …
12 grudnia 2019 12:15
Erik Jan van Leeuwen (Utrecht University)
On Geometric Set Cover for Orthants
We study Set Cover for orthants: Given a set of points in a d-dimensional Euclidean space and a set of orthants of the form (-infty,p_1] x ... x (-infty,p_d], select a minimum number of orthants …
28 listopada 2019 12:15
Petteri Kaski (Department of Computer Science, Aalto University)
Probabilistic tensors and opportunistic Boolean matrix multiplication
We introduce probabilistic extensions of classical deterministic measures of algebraic complexity of a tensor, such as the rank and the border rank. We show that these probabilistic extensions satisfy various natural and algorithmically serendipitous properties, …
14 listopada 2019 12:15
Piotr Sankowski (University of Warsaw)
Walking Randomly, Massively, and Efficiently
We introduce an approach that allows for efficiently generating many independent random walks in big graph models, such as the Massive Parallel Computation (MPC) model. We consider the case where the space per machine is …
7 listopada 2019 12:15
Marcin Pilipczuk (University of Warsaw)
A Polynomial-Time Approximation Scheme for Facility Location on Planar Graphs
We consider the classic Facility Location problem on planar graphs (non-uniform, uncapacitated). Given an edge-weighted planar graph $G$, a set of clients $C\subseteq V(G)$, a set of facilities $F \subseteq V(G)$, and opening costs $w …
31 października 2019 12:15
François Dross (University of Warsaw)
Trees in tournaments
A tournament is an orientation of a complete graph. A digraph is n-unavoidable if it is contained (as a subdigraph) in every tournament of order n. The unavoidability of a digraph D is the minimum …
24 października 2019 13:00
Solon Pissis (CWI)
Even Faster Elastic-Degenerate String Matching via Fast Matrix Multiplication
An elastic-degenerate (ED) string is a sequence of n sets of strings of total length N, which was recently proposed to model a set of similar sequences. The ED string matching (EDSM) problem is to …
24 października 2019 12:15
Krzysztof Nowicki (UWr)
Faster Algorithms for Edge Connectivity via Random 2-Out Contractions
We provide a simple new randomized contraction approach to the global minimum cut problem for simple undirected graphs. The contractions exploit 2-out edge sampling from each vertex rather than the standard uniform edge sampling. We …
17 października 2019 12:15
Stéphane Bessy (LIRMM Montpellier)
Triangle and cycle packing in tournaments: complexity and algorithms
Given a tournament T and a positive integer k, we study different question dealing with packing (oriented) cycles in tournament: does T contain k vertex-disjoint cycles (k-VCT)? k arc-disjoint cycles (k-ACT)? k-arc-disjoint triangles (k-ATT)?, where …
10 października 2019 12:15
Edouard Bonnet (ENS Lyon)
Parameterized Complexity of Grundy Coloring and its variants
(Connected/Partial/Weak) Grundy Coloring, b-Coloring, b-Chromatic Core, etc. are maximization coloring problems, where one asks for the worst case of a first-fit coloring strategy. They were introduced to analyze if some coloring heuristics have performance guarantee. …