| Bernardo Rodrigues, School of Mathematics, Statistics and Computer Science at University of KwaZulu-Natal, South Africa | Bernardo Rodrigues, School of Mathematics, Statistics and Computer Science at University of KwaZulu-Natal, South Africa | Ewing 336 | Title: On linear codes with complementary duals obtained from
permutation modules of finite groups | 6/13/2017 6:00:00 PM | 6/13/2017 7:00:00 PM | False | |
| Ferdinand Ihringer, University of Regina | Ferdinand Ihringer, University of Regina | EWG 336 | Title: Ovoids in Generalizes Quadrangles
Abstract: A
generalized quadrangle
(GQ) of order (
s, t
) consists of a set of points
P
and a set of lines
L
such that (1) each line contains exactly
s
+ 1 points,
(2) each point lies in exactly
t
+ 1 lines, (3) a more technical condition that
prevents triangles, but guarantees the existence of quadrangles. The
point
graph
of a GQ is strongly regular. A coclique of size 1 +
st
of the point
graph is called an
ovoid
. A coclique of smaller size is called a
partial ovoid
.
In the talk we will discuss the existence of ovoids in GQs and, if they do
not exist, bounds on the size of partial ovoids. | 4/26/2017 3:00:00 PM | 4/26/2017 4:00:00 PM | False | |
| Wei-Hsuan Yu, University of Michigan | Wei-Hsuan Yu, University of Michigan | EWG 336 | New bounds for equiangular lines and spherical
two-distance sets
</br></br>
<a href="https://www.mathsci.udel.edu/content-sub-site/Documents/Seminar%20Abstracts/yu_abst_17s.pdf">Abstract</a> | 4/4/2017 3:00:00 PM | 4/4/2017 4:00:00 PM | False | |
| Jason Williford, University of Wyoming | Jason Williford, University of Wyoming | EWG 336 | Title: Q-polynomial association schemes with at most 5 classes
Abstract: An association scheme can be thought of as a combinatorial generalization of a finite transitive permutation group, where the notion of global symmetry is replaced by certain local symmetry conditions. The definition of association scheme is due to Bose and Shimamoto in 1939, in the context of the design of experiments. Since then it has found connections to coding theory, group theory, and finite geometry. In the 1973 thesis of Philippe Delsarte, the author identified two special classes of association schemes: the so-called P-polynomial and Q-polynomial schemes. The schemes that are P-polynomial are precisely those generated by a distance-regular graph, in which Delsarte gave natural analogues to coding theory. Similarly, Delsarte gave a natural analogue to design theory in Q-polynomial schemes. However, Q-polynomial schemes have no analogous combinatorial definition. Consequently, much less is known about them then their P-polynomial counterparts. In this talk, we will discuss what is known about primitive 3-class Q-polynomial schemes, and imprimitive Q-polynomial schemes with at most 5 classes. We will also present new tables of parameter sets summarizing known constructions, non-existence results and open cases. | 3/17/2017 3:00:00 PM | 3/17/2017 4:00:00 PM | False | |
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