Combinatorics Seminar 2015

Speaker: Qing Xiang (向青), University of Delaware

Date: Sat, Sep 26, 2015

Time: 09:00 - 10:00

Venue: Middle Meeting Room

Title: Tight sets and $m$-ovoids of quadrics


This is a talk about tight sets and $m$-ovoids of classical polar spaces. Tight sets and $m$-ovoids are important substructures of classical polar spaces. They are not only interesting in their own right, but also can give rise to other geometric/combinatorial objects, such as translation planes, strongly regular graphs, two-weight codes, etc. In this talk, we will talk about a construction of $\frac{q^2-1}{2}$-tight sets of $Q^{+}(5,q)$, the Klein quadric, for $q\equiv 5$ or $9\pmod{12}$, and a recent construction of $\frac{q-1}{2}$-ovoids of $Q(4,q)$, the parabolic quadric of $PG(4,q)$, for $q\equiv 3\pmod 4$.

Joint work with Tao Feng and Koji Momihara.

Slides: View slides