Group Actions and Dynamics Seminar: Difference between revisions
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During the Fall 2025 semester, '''RTG / Group Actions and Dynamics''' seminar meets in room ''' | During the Fall 2025 semester, '''RTG / Group Actions and Dynamics''' seminar meets in room '''B123 Van Vleck''' on '''Mondays''' from '''2:25pm - 3:15pm'''. To sign up for the mailing list send an email from your wisc.edu address to dynamics+join@g-groups.wisc.edu. For more information, contact Paul Apisa, Tullia Dymarz, Autumn Kent, Marissa Loving, Caglar Uyanik, Chenxi Wu or Andy Zimmer. | ||
== Fall | == Fall 2025 == | ||
{| cellpadding="8" | {| cellpadding="8" | ||
| Line 11: | Line 11: | ||
|- | |- | ||
|September 8 | |September 8 | ||
| | |[https://sites.google.com/view/algebrandis/ Brandis Whitfield] (UW) | ||
| | |Constructing reducibly geometrically finite subgroups of the mapping class group | ||
| | |local | ||
|- | |- | ||
|September 15 | |September 15 | ||
| | |[https://sites.google.com/site/jhdezhdez/ Jesús Hernández Hernández] (UNAM) | ||
| | |Uncountably-many ways of cooking fibrations of handlebodies* | ||
| | |Loving | ||
|- | |- | ||
|September 22 | |September 22 | ||
|[https://sites.google.com/view/junmo-ryang-math/home Junmo Ryang] (Rice) | |||
|Pseudo-Anosov Subgroups of Surface Bundles over Tori | |||
|Loving and Uyanik | |||
|- | |||
|September 29 | |||
|[https://sites.google.com/view/jagerynn Jagerynn Verano] (UIC) | |||
|TBA | |||
|Loving | |||
|- | |||
|October 6 | |||
|[https://sites.google.com/wisc.edu/vickywen/ Vicky Wen] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|October 13 | |||
| | | | ||
| | | | ||
| | | | ||
|- | |- | ||
| | |October 20 | ||
| | |[https://gauss.math.yale.edu/~dk929/ Dongryul Kim] (Yale) | ||
| | |TBA | ||
|Zimmer | |||
|- | |||
|October 27 | |||
|[https://sites.google.com/view/niclas-technaus-website Niclas Technau] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|November 3 | |||
|[https://scse.d.umn.edu/faculty-staff/neil-hoffman-0 Neil Hoffman] (UMN-Duluth) | |||
|TBA | |||
|Uyanik | |||
|- | |||
|November 10 | |||
| [https://wuchenxi.github.io/ Chenxi Wu] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|November 17 | |||
|[https://sites.google.com/view/lovingmath/home Marissa Loving] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|November 24 | |||
|[https://people.math.wisc.edu/~amzimmer2/ Andrew Zimmer] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|December 1 | |||
|[https://www.caglaruyanik.com/home Caglar Uyanik] (UW) | |||
|TBA | |||
|local | |||
|- | |||
|December 8 | |||
|reserved | |||
|TBA | |||
| | | | ||
|- | |- | ||
| Line 33: | Line 83: | ||
== Fall Abstracts == | == Fall Abstracts == | ||
===Brandis Whitfield=== | |||
A longstanding goal within low-dimensional geometry and topology is to establish parallels between the theory of Kleinian groups and subgroups of the mapping class group. Convex-cocompact subgroups of the mapping class group have been well studied in the past few decades; current research aims to extend this analogy to the more general class of geometric finiteness. Dowdall–Durham–Leininger–Sisto introduce parabolically geometrically finite (PGF) subgroups of the mapping class group whose coned-off Cayley graphs, with respect to a collection of twist subgroups, quasi-isometrically embed into the curve complex. In joint work with Aougab, Bray, Dowdall, Hoganson and Maloni, we extend this definition to allow the coned-off subgroups to be more generally reducible, and produce plentiful examples of this behavior. Our examples include free products of reducible subgroups and the beloved right-angled Artin constructions of Clay–Mangahas–Leininger. | |||
=== Jesús Hernández Hernández=== | |||
In this talk we introduce a Denjoy homeomorphisms of the circle, which can be thought as "irrational rotations of the circle that leave an invariant Cantor set". Using these homeomorphisms we create uncountably-many homeomorphisms of the Cantor-tree surface, all of which have mapping torus homeomorphic to (the interior of) a genus 2 handlebody. Finally, we show some variations of this construction to a) fiber any genus g > 1 handlebody with Cantor-tree surfaces, and b) how can we modify the construction of the homeomorphisms for this result to be applied to different surfaces. This is joint work with Christopher J. Leininger and Ferrán Valdez. | |||
===Junmo Ryang=== | |||
In 2002, Farb and Mosher introduced the notion of convex cocompactness in the mapping class group to capture coarse geometric information of the associated surface group extensions. Convex cocompact subgroups are necessarily finitely generated and purely pseudo-Anosov, but it is an open question whether the converse is true. Several partial results are known in certain settings, however. For example, work of Dowdall, Kent, Leininger, Russell, and Schleimer give a positive answer for subgroups of fibered 3-manifold groups (aka surface-by-cyclic extensions) naturally embedded in punctured mapping class groups via the Birman exact sequence. We present a generalization of this in the setting of surface-by-abelian extensions. | |||
=== Jagerynn Verano === | |||
===Vicky Wen=== | |||
===Dongryul Kim=== | |||
===Niclas Technau=== | |||
===Neil Hoffman=== | |||
===Chenxi Wu=== | |||
===Marissa Loving=== | |||
===Andrew Zimmer=== | |||
===Caglar Uyanik=== | |||
== Archive of past Dynamics seminars== | |||
2024-2025 [[Dynamics_Seminar_2024-2025]] | |||
2023-2024 [[Dynamics_Seminar_2023-2024]] | |||
2022-2023 [[Dynamics_Seminar_2022-2023]] | |||
2021-2022 [[Dynamics_Seminar_2021-2022]] | |||
2020-2021 [[Dynamics_Seminar_2020-2021]] | |||
Latest revision as of 18:46, 2 September 2025
During the Fall 2025 semester, RTG / Group Actions and Dynamics seminar meets in room B123 Van Vleck on Mondays from 2:25pm - 3:15pm. To sign up for the mailing list send an email from your wisc.edu address to dynamics+join@g-groups.wisc.edu. For more information, contact Paul Apisa, Tullia Dymarz, Autumn Kent, Marissa Loving, Caglar Uyanik, Chenxi Wu or Andy Zimmer.
Fall 2025
| date | speaker | title | host(s) |
|---|---|---|---|
| September 8 | Brandis Whitfield (UW) | Constructing reducibly geometrically finite subgroups of the mapping class group | local |
| September 15 | Jesús Hernández Hernández (UNAM) | Uncountably-many ways of cooking fibrations of handlebodies* | Loving |
| September 22 | Junmo Ryang (Rice) | Pseudo-Anosov Subgroups of Surface Bundles over Tori | Loving and Uyanik |
| September 29 | Jagerynn Verano (UIC) | TBA | Loving |
| October 6 | Vicky Wen (UW) | TBA | local |
| October 13 | |||
| October 20 | Dongryul Kim (Yale) | TBA | Zimmer |
| October 27 | Niclas Technau (UW) | TBA | local |
| November 3 | Neil Hoffman (UMN-Duluth) | TBA | Uyanik |
| November 10 | Chenxi Wu (UW) | TBA | local |
| November 17 | Marissa Loving (UW) | TBA | local |
| November 24 | Andrew Zimmer (UW) | TBA | local |
| December 1 | Caglar Uyanik (UW) | TBA | local |
| December 8 | reserved | TBA |
Fall Abstracts
Brandis Whitfield
A longstanding goal within low-dimensional geometry and topology is to establish parallels between the theory of Kleinian groups and subgroups of the mapping class group. Convex-cocompact subgroups of the mapping class group have been well studied in the past few decades; current research aims to extend this analogy to the more general class of geometric finiteness. Dowdall–Durham–Leininger–Sisto introduce parabolically geometrically finite (PGF) subgroups of the mapping class group whose coned-off Cayley graphs, with respect to a collection of twist subgroups, quasi-isometrically embed into the curve complex. In joint work with Aougab, Bray, Dowdall, Hoganson and Maloni, we extend this definition to allow the coned-off subgroups to be more generally reducible, and produce plentiful examples of this behavior. Our examples include free products of reducible subgroups and the beloved right-angled Artin constructions of Clay–Mangahas–Leininger.
Jesús Hernández Hernández
In this talk we introduce a Denjoy homeomorphisms of the circle, which can be thought as "irrational rotations of the circle that leave an invariant Cantor set". Using these homeomorphisms we create uncountably-many homeomorphisms of the Cantor-tree surface, all of which have mapping torus homeomorphic to (the interior of) a genus 2 handlebody. Finally, we show some variations of this construction to a) fiber any genus g > 1 handlebody with Cantor-tree surfaces, and b) how can we modify the construction of the homeomorphisms for this result to be applied to different surfaces. This is joint work with Christopher J. Leininger and Ferrán Valdez.
Junmo Ryang
In 2002, Farb and Mosher introduced the notion of convex cocompactness in the mapping class group to capture coarse geometric information of the associated surface group extensions. Convex cocompact subgroups are necessarily finitely generated and purely pseudo-Anosov, but it is an open question whether the converse is true. Several partial results are known in certain settings, however. For example, work of Dowdall, Kent, Leininger, Russell, and Schleimer give a positive answer for subgroups of fibered 3-manifold groups (aka surface-by-cyclic extensions) naturally embedded in punctured mapping class groups via the Birman exact sequence. We present a generalization of this in the setting of surface-by-abelian extensions.
Jagerynn Verano
Vicky Wen
Dongryul Kim
Niclas Technau
Neil Hoffman
Chenxi Wu
Marissa Loving
Andrew Zimmer
Caglar Uyanik
Archive of past Dynamics seminars
2024-2025 Dynamics_Seminar_2024-2025
2023-2024 Dynamics_Seminar_2023-2024
2022-2023 Dynamics_Seminar_2022-2023
2021-2022 Dynamics_Seminar_2021-2022
2020-2021 Dynamics_Seminar_2020-2021