Andrew Putman (Notre Dame) - The Johnson filtration is finitely generated
Опубликовано: 31 Август 2026
на канале: 2017-2018 Warwick EPSRC Symposium on Geometry, Topology and Dynamics in Low Dimensions
на канале: 2017-2018 Warwick EPSRC Symposium on Geometry, Topology and Dynamics in Low Dimensions
246
4
Geometry of Teichmüller space and mapping class groups
13 April 2018
Abstract: A recent breakthrough of Ershov-He shows that the Johnson kernel subgroup of the mapping class group is finitely generated for g at least 12. In joint work with Ershov and Church, I have extended this to show that every term of the lower central series of the Torelli group is finitely generated once the genus is sufficiently large. A byproduct of our work is a proof that the Johnson kernel is finitely generated for g at least 4 which is remarkably simple (so simple, in fact, that I will be able to give in nearly complete detail in this talk).