1st February 2005<br>
Andrew Thomason, Claire College, Cambridge,
speaks on <br>
"Forcing minors in graphs" <br>
<br>

The impetus for the study of minors (or contractions) of graphs can be
traced back to Kuratowski's classical theorem about planar graphs, as well
as to the work of Wagner on the four colour conjecture, which gave rise to
Hadwiger's conjecture. What forces certain minors to appear in graphs has
become much better understood lately; we describe this progress and the
connection with (pseudo-)randomness in graphs.