An invariant for free-by-cyclic groups
- đ¤ Speaker: Radhika Gupta (Tata Institute of Fundamental Research)
- đ Date & Time: Wednesday 17 September 2025, 11:00 - 12:00
- đ Venue: Seminar Room 2, Newton Institute
Abstract
For a free group outer automorphism we define `lamination depth’ to be the length of the longest properly nested sequence of its attracting laminations. I will talk about joint work with Spencer Dowdall, Yassine Geurch, Jean Pierre Mutanguha and Caglar Uyanik, where we show that lamination depth is a group invariant of a free-by-cyclic group. That is, a free-by-cyclic group can be viewed as the mapping torus of a free group outer automorphism in multiple ways and we show that each such outer automorphism has the same lamination depth.
Series This talk is part of the Isaac Newton Institute Seminar Series series.
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Radhika Gupta (Tata Institute of Fundamental Research)
Wednesday 17 September 2025, 11:00-12:00