�� <!DOCTYPE html> <html> <head> <style type="text/css"> body { font-family:Verdana; background-color:#F5F5F5; } div.horizontal { } div.horizontal ul { list-style-type:none; margin:0; padding:0; border-width:0px; } div.horizontal li { float:left; width:14.28%; } div.horizontal a { display:block; } div.horizontal a:link,div.horizontal a:visited { font-weight:bold; color:#111111; background-color:#FFFFFF; text-align:center; padding-bottom:19px; padding-top:19px; text-decoration:none; width:100%; } div.horizontal a:hover,div.horizontal a:active { background-color:#FFD700; } div.initbox { display:block; font-weight:bold; font-size:26px; color:#FFFFFF; background-color:#1E90FF; text-align:center; padding-bottom:10px; padding-top:20px; text-decoration:none; } #thispage { background-color:#FFD700; } </style> <title>Combinatorics</title> <script type="text/javascript" async src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-MML-AM_CHTML"> </script> </head> <body> <div class="initbox">Combinatorial group</div> <div class="horizontal"><ul> <li><a href="index.html" >Main page</a></li> <li><a href="people.html">People</a></li> <li><a href="seminar.html" id="thispage">Seminar </a></li> <li><a href="events.html">Events</a></li> <li><a href="students.html">Openings</a></li> <li><a href="outputs.html">Outputs</a></li> <li><a href="fundings.html">Funding</a></li> </ul> </div> <!-- Math code: <img src="http://latex.codecogs.com/gif.latex? THE CODE " border="0"/> --> <hr> <h2>We are shocked by the aggression happening to Ukraine. As citizens we try to help her people with our private means. As professional mathematicians, we welcome suggestions that might help our fellow Ukrainian colleagues (students or researchers) in any way. Some funds may be available to this end. Do not hesitate to contact us!</h2> <hr> <h2>Programme</h2> <p><b> Monday 14.3.2022 at 10:00 <a href="http://www.ustavinformatiky.cz/">ICS</a>, room TBA, <a href="http://honza.ucw.cz/">Jan Volec</a> (Czech Technical University): TBA</b></p> <p><u>Abstract</u>: TBA </p> <h2>Past Seminars</h2> <p><b> Monday 28.2.2022 at 10:00 <a href="http://www.ustavinformatiky.cz/">ICS</a>, <a style="color:red;"> room 262 </a> </b> (next to the office of the speaker)<b>, <a>Diana Piguet</a> (ICS CAS): Perfect packing of degenerate graphs</b></p> <p><u>Abstract</u>: A family of graphs packs into a host graph if there are edge-disjoint copies of every element of the family in the host graph. I shall talk about perfectly packing degenerate graphs of sublinear maximum degree into complete graphs. This work has been motivated by two beautiful tree-packing conjectures &mdash; one of Ringel from 1963 and one of Gy&aacute;rf&aacute;s from 1976. This is joint work with Peter Allen, Julia B&ouml;ttcher, Dennis Clemens, Jan Hladk&yacute;, and Anusch Taraz.</p> <p><b> Monday 14.2.2022 at 10:00 <a href="http://www.ustavinformatiky.cz/">ICS</a>, room 419, <a>Eng Keat Hng</a> (ICS CAS): Minimum degree conditions for powers of cycles and paths</b></p> <p><u>Abstract</u>: We study minimum degree conditions under which a graph G contains kth powers of paths and cycles of arbitrary specified lengths. We determine precise thresholds, assuming that the order of $G$ is large. This extends a result of Allen, B�ttcher and Hladk� [J. Lond. Math. Soc. (2) 84(2) (2011), 269--302] concerning the containment of squares of paths and squares of cycles of arbitrary specified lengths and settles a conjecture of theirs in the affirmative. </p> <p><b>Monday 7.2.2022 at 10:00 <a href="http://www.ustavinformatiky.cz/">ICS</a>, room 419, <a href="https://kam.mff.cuni.cz/~tyomkyn/">Mykhaylo Tyomkyn</a> (Charles University): Limiting constants for weak saturation of hypergraphs</b></p> <p><u>Abstract</u>: For two r-uniform hypergraphs G and H we say that G is weakly H-saturated if the missing edges in G can be filled one by one, creating a new copy of H at every step. The quantity wsat(n,H) measures the smallest size of a weakly H-saturated r-graph of order n. For r=2 a short argument due to Alon (1985) shows that for any graph H, wsat(n,H)/n tends to a limit as n increases. Tuza conjectured in 1992 that for arbitrary r the quantity wsat(n,H)/n^{r-1} similarly has a limit c(H). I will present a recent proof of Tuza's conjecture.</p> <p>Joint work with Asaf Shapira (Tel Aviv University).</p> <p><b>Wednesday 12.1.2022 at 10:00 <a href="http://www.ustavinformatiky.cz/">ICS</a>, room 318, <a href="https://homepages.warwick.ac.uk/staff/Jan.Grebik/">Jan Greb&iacute;k</a> (Warwick): Local problems on bounded degree graphs</b></p> <table width="100%" border="0"> <tr> <td width="25%" height="220" align="center"> <img src="seminar-pictures/Grebik2022.jpg" width="300" class="fltrt"/> </td> <td width="75%"><p><strong></strong></p> <p><u>Abstract</u>: I will discuss some recent progress on connections between distributed computing and descriptive combinatorics. The connection is phrased in the language of local problems, i.e., coloring problems where a correctness of a given candidate coloring can be checked locally. In both fields, the goal is to understand how difficult is to produce a coloring that solves a given local problem. I will focus on the case of oriented paths, however, if time permits we might discuss other classes of graphs. This is joint work Vasek Rozhon.</p> </td> </tr> </table> <hr> <h2><a href="seminar2021.html">seminars in 2021</a></h2> <h2><a href="seminar2020.html">seminars in 2020</a></h2> <h2><a href="seminar2019.html">seminars in 2019</a></h2> <h2><a href="seminar2018.html">seminars in 2018</a></h2> <h2><a href="seminar2017.html">seminars in 2017</a></h2> <h2><a href="seminar2016.html">seminars in 2016</a></h2> </BODY> </HTML>