Better Quasi Orderings

Photograph of Thomas Forster

Thomas Forster

(Cambridge)

These were invented by the late combinatorist Crispin Nash-Williams and most of the work on them has been done by combinatorist. However, much of BQO has an underlying logical/algebraic flavour which I will attempt to bring out. Specifically I shall sketch a proof that a quasiorder is a BQO iff its free countable completion is wellfounded.

I shall try to aim this at a general logical audience, the presence of local BQO-istes notwithstanding.
Thursday 10th June 2004, 15:00
Robert Recorde Room
Department of Computer Science