-Title: RAAGs in Diffeos

- Speaker:Prof. Sang-hyun Kim (Seoul National University)

- Abstract: A right-angled Artin group (RAAG) often admits a natural homomorphism into diffeomorphism groups of manifolds, using the fact that two diffeomorphisms with disjoint supports commute. It is a nontrivial task to reinforce this map to become an embedding. We show that an arbitrary RAAG embeds, by a quasi-isometry, into a pure braid group and also into the area-preserving diffeomorphism groups of the disk and of the sphere. We also show that every RAAG embeds into the real line smooth diffeomorphism group. This gives a rich source of embeddings from fundamental groups of manifolds into various diffeomorphism groups. (Joint work with Thomas Koberda, and partly with Hyungryul Baik)

- Place: Math Science bldg. Room 404

- Date: 3 p.m.- on Wednesday, April 22, 2015

Organized by Jae Choon Cha, Kang-Tae Kim, and Yong-Geun Oh