Eguchi, Ooguri and Tachikawa (EOT) initiated a new era in moonshine in 2010, by observing a relationship between representations of the Mathieu group M24 and the elliptic genus of a K3 surface. As it ties in Calabi-Yau geometry and supersymmetric string theory, this Mathieu moonshine observation has generated a lot of interest and activity. By now Mathieu moonshine has been recognized as a special case of umbral moonshine, and several other new instances of moonshine have been discovered in recent years. The relationship between K3 (sigma model) symmetries and M24 has been clarified, but not in a way that resolves the EOT observation. There are many important questions that will take time to solve.
The topic of this workshop is moonshine phenomena, and should be understood in the broadest sense. Current interesting topics that we plan to cover at the workshop are the following: