#
The Caccetta-Haggkvist conjecture

January 30 to February 3, 2006
at the

American Institute of Mathematics,
Palo Alto, California

organized by

Maria Chudnovsky,
Paul Seymour,
and Robin Thomas

## Original Announcement

This workshop will focus on the
Caccetta-Haggkvist conjecture, which in its simplest form asserts the
following:
If *G* is an *n*-vertex directed graph with
minimum outdegree at least *n/k*,
then *G* has a directed cycle of length at most *k*.

This has a number of variants and strengthenings, and in particular it has
numerous connections with additive number theory. The workshop aims
to clarify and develop these variants, and to bring together people
working on different aspects of the conjecture in the hope of
finding a solution.

## Material from the workshop

A list of participants.
The workshop schedule.

A report on the workshop activities.