16:00 Hoofdvoordracht Andries Brouwer en Hans Cuypers (TU/e)
16:50 Co-referaat door Remco van der Hofstad
How useful, special, and unique are generalized polygons?
Andries Brouwer en Hans Cuypers
A generalized n-gon is a graph (finite or not) of diameter n and girth 2n. A generalized polygon is
a graph that is a generalized n-gon for some n.
Generalized polygons originated in Tits' work on Lie groups and their finite analogues. They are
what buildings are made of.
In computer science and extremal graph theory generalized polygons play a role as the smallest
graphs with given valency and girth,
or the largest graphs with given valency and diameter. They are good expanders.