Research Seminar Combinatorics

On Wednesday the 19th of January 2017, at 10:15 in Takustr. 9, SR 046

William T. Trotter (Georgia Institute of Technology)

will give a talk on

Dimension and Cut Vertices.

When: On Thursday 19.01.2017, at 10:15.

Where: At Takustr. 9 , 14195 Berlin, in room SR 046 .

Abstract: Motivated by quite recent research involving the relationship between the dimension of a poset and graph theoretic properties of its cover graph, we show that for every $d\ge 1$, if $P$ is a poset and the dimension of a subposet $B$ of $P$ is at most~$d$ whenever the cover graph of $B$ is a block of the cover graph of $P$, then the dimension of $P$ is at most $d+2$. We also construct examples which show that this inequality is best possible. We consider the proof of the upper bound to be fairly elegant and relatively compact. However, we know of no simple proof for the lower bound, and our argument requires a powerful tool known as the Product Ramsey Theorem. As a consequence, our constructions involve posets of enormous size. Joint research with Bartosz Walczak and Ruidong Wang



Schedule and abstracts:

Schedule and abstracts 2016/2017



Schedule and abstracts 2015/2016

Schedule and abstracts 2014/2015

Schedule and abstracts 2013/2014

Schedule and abstracts 2012/2013

Schedule and abstracts 2011/2012

Schedule and abstracts 2010/2011

Schedule and abstracts 2009/2010



Mailing list:

To subscribe to the mailing-list of the seminar, please follow this link:


Seminar calendar:

The HTML version of the calendar is hosted here:
HTML calendar.

To add the .ics file of the calendar to your favorite calendar reader (that supports the ICal format), please follow this link:
ICal calendar.

To add the calendar feeds to your favorite feed reader, please follow this link:
Calendar feeds.



For any request, please send an e-mail to: