Dynamics, Rigidity and Arithmetic in Hyperbolic Geometry
Institute for Computational and Experimental Research in Mathematics (ICERM)
May 15, 2023 - May 19, 2023
Your device timezone is . Do you want to view schedules in or choose a custom timezone?
Monday, May 15, 2023
-
9:30 - 9:50 am EDTCheck In / AM Coffee BreakCheck In - 11th Floor Collaborative Space
-
9:50 - 10:00 am EDTWelcome11th Floor Lecture Hall
-
10:00 - 10:45 am EDTHyperbolic geometry - An Introduction11th Floor Lecture Hall
- Speaker
- Ian Biringer, Boston College
- Session Chair
- David Fisher, Rice University
Abstract
The aim of this minicourse is to introduce fundamental concepts in hyperbolic geometry, such as limit sets, geometric finiteness, and critical exponent, and Mostow rigidity. We will discuss examples of arithmetic hyperbolic manifolds, and illustrate flexible geometric constructions like Dehn filling, quasi-conformal deformation, and the gluing constructions of non-arithmetic lattices by Gromov and Piatetski-Shapiro.
-
11:00 - 11:45 am EDTTotally geodesic subvarieties via Hodge theory11th Floor Lecture Hall
- Speaker
- Gregorio Baldi, Institut des Hautes Études Scientifiques
- Session Chair
- David Fisher, Rice University
Abstract
In this Mini Course, following a joint work with E.Ullmo, I will explain how (integral) Hodge theory naturally comes up in the study of totally geodesic subvarieties of a complex hyperbolic ball quotient S. From such a point of view, the finiteness of the maximal totally geodesics of S becomes a consequence of a very general conjecture about 'unlikely intersections'. The two lectures will give some motivations and an introduction to such techniques (no prior knowledge in Hodge theory will be assumed).
-
12:00 - 1:30 pm EDTLunch/Free Time
-
1:30 - 2:15 pm EDTGeometric, dynamical and arithmetic properties of Anosov representations11th Floor Lecture Hall
- Speaker
- Anna Wienhard, Heidelberg University
- Session Chair
- Nattalie Tamam, University of Michigan
Abstract
Anosov representations provides a rich class of discrete embeddings of hyperbolic groups into semisimple Lie groups, which generalizes the classes of convex cocompact subgroups to the setting of higher rank Lie groups. In this talk I will discuss some results (old and new) regarding geometric, dynamical and arithmetic properties.
-
2:30 - 3:15 pm EDTHyperbolic geometry - An Introduction11th Floor Lecture Hall
- Speaker
- Ian Biringer, Boston College
- Session Chair
- Nattalie Tamam, University of Michigan
Abstract
The aim of this minicourse is to introduce fundamental concepts in hyperbolic geometry, such as limit sets, geometric finiteness, and critical exponent, and Mostow rigidity. We will discuss examples of arithmetic hyperbolic manifolds, and illustrate flexible geometric constructions like Dehn filling, quasi-conformal deformation, and the gluing constructions of non-arithmetic lattices by Gromov and Piatetski-Shapiro.
-
3:30 - 4:00 pm EDTCoffee Break11th Floor Collaborative Space
-
4:00 - 4:45 pm EDTRigidity and geodesic planes in infinite volume hyperbolic manifolds11th Floor Lecture Hall
- Speaker
- Hee Oh, Yale university
- Session Chair
- Nattalie Tamam, University of Michigan
Abstract
The aim of this mini course is to discuss some basic theory of homogeneous dynamics on the quotient of SO(n,1) by a discrete subgroup and to explain the topological rigidity of geodesic planes in hyperbolic n-manifolds of Fuchsian ends which was proved by McMullen-Mohammadi-O. (for n=3) and by Minju Lee-O. (for n>3).
-
5:00 - 6:30 pm EDTReception11th Floor Collaborative Space
Tuesday, May 16, 2023
-
9:30 - 10:00 am EDTCoffee Break11th Floor Collaborative Space
-
10:00 - 10:45 am EDTArithmeticity, superrigidity, and totally geodesic manifolds11th Floor Lecture Hall
- Speaker
- Nicholas Miller, University of Oklahoma
- Session Chair
- Alan Reid, Rice University
Abstract
In the 1970s seminal work of Margulis showed that higher rank lattices have superrigid representations, which in particular implies that all such lattices are arithmetic. Since then Gromov–Piatetski-Shapiro and Deligne–Mostow have shown that a similar superrigidity theorem cannot hold for all lattices in the isometry group of real or complex hyperbolic space, i.e., in the rank 1 setting. However in recent work joint with Bader, Fisher, and Stover we show that one can prove certain superrigidity/arithmeticity theorems provided the associated manifold satisfies the geometric condition that it contains infinitely many (maximal) totally geodesic submanifolds. Specifically, we show that this latter criteria forces a hyperbolic manifold to be arithmetic.
The goal of this mini-course will be first to recount the work of Margulis on superrigidity of higher rank lattices and then to go on to discuss the proof of the aforementioned theorem. This will include a discussion of the connections between homogeneous dynamics and geodesic submanifolds, their interaction with superrigidity, and an introduction to techniques introduced by Bader and Furman for studying algebraic representations of ergodic actions. If time permits, we will also discuss the analogous theorem for complex hyperbolic manifolds and the key differences from the real hyperbolic setting. -
11:00 - 11:45 am EDTRigidity and geodesic planes in infinite volume hyperbolic manifolds11th Floor Lecture Hall
- Speaker
- Hee Oh, Yale university
- Session Chair
- Alan Reid, Rice University
Abstract
The aim of this mini course is to discuss some basic theory of homogeneous dynamics on the quotient of SO(n,1) by a discrete subgroup and to explain the topological rigidity of geodesic planes in hyperbolic n-manifolds of Fuchsian ends which was proved by McMullen-Mohammadi-O. (for n=3) and by Minju Lee-O. (for n>3).
-
12:00 - 1:30 pm EDTLunch/Free Time
-
1:30 - 2:15 pm EDTTotally geodesic subvarieties via Hodge theory11th Floor Lecture Hall
- Speaker
- Gregorio Baldi, Institut des Hautes Études Scientifiques
- Session Chair
- Dubi Kelmer, Boston College
Abstract
In this Mini Course, following a joint work with E.Ullmo, I will explain how (integral) Hodge theory naturally comes up in the study of totally geodesic subvarieties of a complex hyperbolic ball quotient S. From such a point of view, the finiteness of the maximal totally geodesics of S becomes a consequence of a very general conjecture about 'unlikely intersections'. The two lectures will give some motivations and an introduction to such techniques (no prior knowledge in Hodge theory will be assumed).
-
2:30 - 3:15 pm EDTExponential mixing of frame flows for geometrically finite hyperbolic manifolds11th Floor Lecture Hall
- Speaker
- Pratyush Sarkar, UC San Diego
- Session Chair
- Dubi Kelmer, Boston College
Abstract
The frame bundle of an n-dimensional hyperbolic manifold X is the homogeneous space Γ\SO(n, 1)° for some discrete subgroup Γ and the frame flow is given by the right translation action by a one-parameter diagonalizable subgroup. We assume that Γ is Zariski dense and X is geometrically finite, i.e., it need not be compact but has at most finitely many ends consisting of cusps and funnels. We endow the frame bundle with the unique probability measure of maximal entropy called the Bowen-Margulis-Sullivan measure. In a joint work with Jialun Li and Wenyu Pan, we prove that the frame flow is exponentially mixing. The proof uses a countably infinite coding and the latest version of Dolgopyat's method. To overcome the difficulty in applying Dolgopyat's method due to the cusps of non-maximal rank, we prove a large deviation property for symbolic recurrence to certain large subsets of the limit set of Γ.
-
3:30 - 4:00 pm EDTCoffee Break11th Floor Collaborative Space
-
4:00 - 4:45 pm EDTLength functions in Lie groups and lattices.11th Floor Lecture Hall
- Speaker
- Sebastian Hurtado, Yale University
- Session Chair
- Dubi Kelmer, Boston College
Abstract
We will discuss the notion of length functions on groups, focusing on lattices in Lie groups of higher rank, and discuss how dynamics and ergodic theory can help to understand some questions about them.
Wednesday, May 17, 2023
-
9:30 - 10:00 am EDTCoffee Break11th Floor Collaborative Space
-
10:00 - 10:45 am EDTRigidity and geodesic planes in infinite volume hyperbolic manifolds11th Floor Lecture Hall
- Speaker
- Hee Oh, Yale university
- Session Chair
- David Fisher, Rice University
Abstract
The aim of this mini course is to discuss some basic theory of homogeneous dynamics on the quotient of SO(n,1) by a discrete subgroup and to explain the topological rigidity of geodesic planes in hyperbolic n-manifolds of Fuchsian ends which was proved by McMullen-Mohammadi-O. (for n=3) and by Minju Lee-O. (for n>3).
-
11:00 - 11:45 am EDTArithmeticity, superrigidity, and totally geodesic manifolds11th Floor Lecture Hall
- Speaker
- Nicholas Miller, University of Oklahoma
- Session Chair
- David Fisher, Rice University
Abstract
"In the 1970s seminal work of Margulis showed that higher rank lattices have superrigid representations, which in particular implies that all such lattices are arithmetic. Since then Gromov–Piatetski-Shapiro and Deligne–Mostow have shown that a similar superrigidity theorem cannot hold for all lattices in the isometry group of real or complex hyperbolic space, i.e., in the rank 1 setting. However in recent work joint with Bader, Fisher, and Stover we show that one can prove certain superrigidity/arithmeticity theorems provided the associated manifold satisfies the geometric condition that it contains infinitely many (maximal) totally geodesic submanifolds. Specifically, we show that this latter criteria forces a hyperbolic manifold to be arithmetic.
The goal of this mini-course will be first to recount the work of Margulis on superrigidity of higher rank lattices and then to go on to discuss the proof of the aforementioned theorem. This will include a discussion of the connections between homogeneous dynamics and geodesic submanifolds, their interaction with superrigidity, and an introduction to techniques introduced by Bader and Furman for studying algebraic representations of ergodic actions. If time permits, we will also discuss the analogous theorem for complex hyperbolic manifolds and the key differences from the real hyperbolic setting." -
11:55 am - 12:00 pm EDTGroup Photo (Immediately After Talk)11th Floor Lecture Hall
-
12:00 - 1:30 pm EDTLunch/Free Time
-
1:30 - 2:15 pm EDTDiscrete subgroups with finite Bowen-Margulis-Sullivan measure in higher rank11th Floor Lecture Hall
- Speaker
- Minju Lee, University of chicago
- Session Chair
- Julien Paupert, Arizona State University
Abstract
Let G be a connected semisimple real algebraic group and D be its Zariski dense discrete subgroup. We prove that if D\G admits any finite Bowen-Margulis-Sullivan measure, then D is virtually a product of higher rank lattices and discrete subgroups of rank one factors of G. This may be viewed as a measure-theoretic analogue of classification of convex cocompact actions by Kleiner-Leeb and Quint, which was conjectured by Corlette in 1994. This is joint work with Mikolaj Fraczyk. We will then discuss its application on the bottom of the L^2 spectrum, in joint work with Samuel Edwards, Mikolaj Fraczyk and Hee Oh.
-
2:30 - 3:15 pm EDTBilliards and the arithmetic of non-arithmetic groups11th Floor Lecture Hall
- Speaker
- Curtis McMullen, Harvard University
- Session Chair
- Julien Paupert, Arizona State University
Abstract
We will survey new results and open problems on triangle groups in SL_2(R), and their connections to Abelian varieties, Teichmueller curves and billiards in polygons.
-
3:30 - 4:00 pm EDTCoffee Break11th Floor Collaborative Space
-
4:00 - 4:45 pm EDTUnderstanding geodesic planes in hyperbolic 3-manifolds via computations and visualization11th Floor Lecture Hall
- Speaker
- Yongquan Zhang, Stony Brook University
- Session Chair
- Julien Paupert, Arizona State University
Abstract
As a companion and complement to the mini-course on rigidity of geodesic planes in infinite volume hyperbolic manifolds, I will discuss several examples of rigidity and nonrigidity of geodesic planes in hyperbolic 3-manifolds. These results are orthogonal to the ones obtained by McMullen, Mohammadi and Oh, and illustrate what can happen if some of their assumptions are relaxed. Some of these examples were produced by explicit computations and can be visualized very nicely, and I will discuss these aspects as well.
Thursday, May 18, 2023
-
9:30 - 10:00 am EDTCoffee Break11th Floor Collaborative Space
-
10:00 - 10:45 am EDTArithmeticity, superrigidity, and totally geodesic manifolds11th Floor Lecture Hall
- Speaker
- Nicholas Miller, University of Oklahoma
- Session Chair
- Jane Wang, University of Maine
Abstract
In the 1970s seminal work of Margulis showed that higher rank lattices have superrigid representations, which in particular implies that all such lattices are arithmetic. Since then Gromov–Piatetski-Shapiro and Deligne–Mostow have shown that a similar superrigidity theorem cannot hold for all lattices in the isometry group of real or complex hyperbolic space, i.e., in the rank 1 setting. However in recent work joint with Bader, Fisher, and Stover we show that one can prove certain superrigidity/arithmeticity theorems provided the associated manifold satisfies the geometric condition that it contains infinitely many (maximal) totally geodesic submanifolds. Specifically, we show that this latter criteria forces a hyperbolic manifold to be arithmetic.
The goal of this mini-course will be first to recount the work of Margulis on superrigidity of higher rank lattices and then to go on to discuss the proof of the aforementioned theorem. This will include a discussion of the connections between homogeneous dynamics and geodesic submanifolds, their interaction with superrigidity, and an introduction to techniques introduced by Bader and Furman for studying algebraic representations of ergodic actions. If time permits, we will also discuss the analogous theorem for complex hyperbolic manifolds and the key differences from the real hyperbolic setting. -
11:00 - 11:45 am EDTUniform spectral gap and orthogeodesic counting for Kleinian groups11th Floor Lecture Hall
- Speaker
- Beibei Liu, University of California, Davis
- Session Chair
- Jane Wang, University of Maine
Abstract
Strongly convergent sequences of hyperbolic manifolds arise naturally in the study of Kleinian group representations, for example, the Dehn surgeries on hyperbolic knots. It turns out that such sequences usually have uniform control on the geometry and dynamics, such as the uniform convergence of small eigenvalues of the Laplacian, and the Patterson-Sullivan measures. We will talk about the uniform convergence results in this talk and apply them to count uniformly along the sequence the number of simple closed geodesics and orthogeodesics. This is joint work with Franco Vargas Pallete.
-
12:00 - 1:30 pm EDTLunch/Free Time
-
1:30 - 2:15 pm EDTLyapunov spectrum: simplicity and continuity beyond random products11th Floor Lecture Hall
- Speaker
- Alex Furman, University of Illinois at Chicago - UIC
- Session Chair
- Plinio Pino Murillo, Fluminense Federal University
-
2:30 - 3:15 pm EDTIntersection number and intersection points of closed geodesics on hyperbolic surfaces11th Floor Lecture Hall
- Speaker
- Tina Torkaman, Harvard University
- Session Chair
- Plinio Pino Murillo, Fluminense Federal University
Abstract
In this talk, I will discuss the (geometric) intersection number between closed geodesics on finite volume hyperbolic surfaces. Specifically, I talk about the optimum upper bound on the intersection number in terms of the product of hyperbolic lengths. I also talk about the equidistribution of the intersection points between closed geodesics.
-
3:30 - 4:00 pm EDTCoffee Break11th Floor Collaborative Space
-
4:00 - 4:45 pm EDTUnderstanding geodesic planes in hyperbolic 3-manifolds via computations and visualization11th Floor Lecture Hall
- Speaker
- Yongquan Zhang, Stony Brook University
- Session Chair
- Plinio Pino Murillo, Fluminense Federal University
Abstract
As a companion and complement to the mini-course on rigidity of geodesic planes in infinite volume hyperbolic manifolds, I will discuss several examples of rigidity and nonrigidity of geodesic planes in hyperbolic 3-manifolds. These results are orthogonal to the ones obtained by McMullen, Mohammadi and Oh, and illustrate what can happen if some of their assumptions are relaxed. Some of these examples were produced by explicit computations and can be visualized very nicely, and I will discuss these aspects as well.
Friday, May 19, 2023
-
9:30 - 10:00 am EDTCoffee Break11th Floor Collaborative Space
-
10:00 - 10:45 am EDTFourier decay of self-conformal measures for non-linear IFS’s11th Floor Lecture Hall
- Speaker
- Zhiren Wang, Penn State University
- Session Chair
- Bena Tshishiku, Brown University
Abstract
We show that for a C^2 IFS on R, either up to smooth conjugacy the IFS has vanishing second derivative on its attractor, or the self-conformal measure has polynomial decay of Fourier coefficients. A key argument is a cocycle version of Dolgopyat's method and resulting spectral gap-type estimates and renewal theorem. This is a joint work with Amir Algom and Federico Rodriguez Hertz.
-
11:00 - 11:45 am EDTCentral extensions of real and complex hyperbolic lattices11th Floor Lecture Hall
- Speaker
- Matthew Stover, Temple University
- Session Chair
- Bena Tshishiku, Brown University
Abstract
I will describe joint work with Domingo Toledo on residual finiteness for cyclic central extensions of fundamental groups of aspherical manifolds, its application to central extensions of (arithmetic) real and complex hyperbolic lattices, and connections to several open problems.
-
12:00 - 1:30 pm EDTLunch/Free Time
-
1:30 - 2:15 pm EDTPoisson-Voronoi tessellations in higher rank and the fixed price conjecture11th Floor Lecture Hall
- Speaker
- Mikolaj Fraczyk, University of Chicago
- Session Chair
- Dubi Kelmer, Boston College
Abstract
The cost of a probability measure preserving action of a countable group G on X is an invariant that generalizes the rank (minimal number of generators) of G and measures the “minimal average number of maps” needed to connect every pair of points of X in the same G orbit. The fixed price conjecture predicts that any two essentially free p.m.p. actions of the group G have the same cost. In my talk I will report on a joint work with Sam Mellick and Amanda Wilkens in which we prove fixed price one for higher ranks lattices in semisimple real or p-adic groups. As a corollary we obtain that the number of generators of index n subgroup of such a group grows like o(n) which implies new state of the art results on the growth of mod-p homology groups. The proof is based on certain miraculous properties of the Poisson-Voronoi tessellation of higher rank symmetric spaces (not present in rank 1) that might be of independent interest.
-
2:30 - 3:15 pm EDTThe arithmetic of totally geodesic surfaces on Bianchi orbifolds11th Floor Lecture Hall
- Speaker
- Junehyuk Jung, Brown University
- Session Chair
- Dubi Kelmer, Boston College
Abstract
Bianchi subgroups are cofinite non-cocompact lattices in PSL_2(C), defined by \Gamma_d = PSL_2(O_d), where O_d is the ring of integers of the imaginary quadratic field of discriminant -d. The Bianchi orbifold \Omega_d = \Gamma_d\H^3 is known to contain infinitely many immersed totally geodesic surfaces, which can be identified with integral binary hermitian forms over O_d. In this talk, I will show that some of these immersed totally geodesic surfaces are in fact orientable embedded closed totally geodesic surfaces using number theoretic ideas. I then present some numerical data concerning these surfaces. This talk is based on a joint work with Alan Reid and on an ongoing project with Sam Kim and James Rickards.
-
3:30 - 4:00 pm EDTCoffee Break11th Floor Collaborative Space
All event times are listed in ICERM local time in Providence, RI (Eastern Daylight Time / UTC-4).
All event times are listed in .
ICERM local time in Providence, RI is Eastern Daylight Time (UTC-4). Would you like to switch back to ICERM time or choose a different custom timezone?
Schedule Timezone Updated