# Dartmouth Mathematics Colloquium

4:00-5:00 pm

## Professor Jean Larson

speaks on

### An Ordinal Partition Omitting Pentagons.

Abstract. This talk will focus on ordinary partition relations for countable ordinal numbers, starting with a brief survey of known results and ending with an overview of the proof that $\omega^{\omega^2}\not\rightleftarrow(\omega^{\omega^2},5)^2$.
The talk uses Halloween imagery (bats, witches to a lesser extent,
and vampires), overhead transparencies, and post-it notes to discuss the partition.

Tea.
High tea will be served at 3:30 pm in the Lounge.
Emmy's. Certain refreshments will be served at Emmy's after the talk.
Host. Jim Baumgartner is the host. Anybody who is interested in having dinner with the speaker should contact Jim at 646-3559.