Study ping-pong dynamics in hyperbolic-like groups with non-simple points.
problem Investigate the ping-pong dynamics of hyperbolic-like groups.
method Explicitly provide a proper ping-pong partition for any pair of non-cyclic point stabilizers.
result Existence of a proper ping-pong partition for any pair of non-cyclic point stabilizers.
Study estimates gaps in semigroup products, proving embedding properties.
problem Estimating singular value gaps in semigroup products.
method Lower estimates for singular value gaps of free products of semigroups in ping-pong position.
result Groups generated by semigroups in ping-pong position are quasi-isometrically embedded.
Groups without non-trivial finite normal subgroups have a strong ping pong property.
problem Proving a strong ping pong property for acylindrically hyperbolic groups.
method Proving the Pnaive property for groups with no non-trivial finite normal subgroups. result Groups satisfying the condition have a strong ping pong property.
New groups discovered with unique properties in a specific space.
problem Finding new discrete subgroups with special properties in a mathematical space.
method Proved by showing groups play ping-pong on cones, related to crooked surfaces.
result Infinite family of discrete subgroups with remarkable properties in Sp4(R). New hyperbolic groups from ping-pong automorphisms.
problem Finding new hyperbolic groups from automorphisms.
method Proving generalized north-south dynamics and constructing new subgroups.
result Produced new examples of hyperbolic groups not convex cocompact.
Geometric group theory explores groups through their geometric properties.
problem Understanding groups via geometric properties.
method Cayley and Schreier graphs, ping-pong lemma, quasi-isometries, growth of groups, hyperbolicity.
result Gromov's theorem on groups of polynomial growth and amenability.
This paper models market manipulation using reinforcement learning to detect and counter spoofing and pinging strategies.
problem Detecting and preventing market manipulation, especially spoofing and pinging strategies.
method Reinforcement learning framework applied to Markov decision processes for analyzing trading strategies.
result The model predicts the behavior of manipulators and suggests countermeasures for market regulators.
Algorithm determines discrete, free subgroups of SL2 over non-archimedean fields.
problem Identifying discrete, free subgroups of SL2 over non-archimedean fields.
method Ping Pong Lemma applied to Bruhat-Tits tree action.
result Algorithm determines if subgroup is discrete and free of rank two.
The study examines subgroups of torus mapping class group generated by Dehn twists powers.
problem Characterizing subgroups generated by powers of Dehn twists.
method Using the ping pong lemma and geometric intersection numbers.
result Subgroups can be free groups, direct products, or have specific ranks.
We prove that if φ,ψ∈Out(FN) are hyperbolic iwips (irreducible with irreducible powers) such that <φ,ψ>≤Out(FN) is not virtually cyclic then some high powers of φ and ψ generate a free subgroup of rank two, all of whose nontrivial elements are again hyperbolic iwips. Being a hyperbolic iwip element of $…
The paper proves a quantitative Tits alternative for negatively pinched manifolds.
problem Proving a quantitative version of the Tits alternative for negatively pinched manifolds.
method Analyzing discrete isometry subgroups generated by two non-elliptic isometries.
result A free subgroup of rank 2 is found in the isometry subgroup, which is convex-cocompact when one of the generators is hyperbolic.
Local-to-global principle for Morse actions on symmetric spaces.
problem Recognizing Morse actions on symmetric spaces.
method Equivariant Morse quasiisometric embeddings of trees into symmetric spaces.
result Algorithmic recognizability of Morse actions and construction of Morse Schottky subgroups.
We prove that the cotangent of a double Lie groupoid S has itself a double groupoid structure with sides the duals of associated Lie algebroids, and double base the dual of the Lie algebroid of the core of S. Using this, we prove a result outlined by Weinstein in 1988, that the side groupoids of a general symplectic do…
Researchers discover all affinely homogeneous models for surfaces in 4D space.
problem Identifying all affinely homogeneous models for surfaces in 4D space.
method Improved power series method of equivalence, capturing invariants at the origin, creating branches, and infinitesimalizing calculations.
result Find several inequivalent terminal branches yielding each to some nonempty moduli space of homogeneous models.
Paper presents certified defenses against adversarial patch attacks.
problem Certified defenses against adversarial patch attacks are needed.
method Proposes the first certified defense and faster training methods.
result Demonstrates robustness transfer across different patch shapes.
We define an abstract notion of double Lie algebroid, which includes as particular cases: (1) the double Lie algebroid of a double Lie groupoid in the sense of the author, such as the iterated tangent bundle of an ordinary manifold, and various iterated tangent/cotangent constructions in symplectic and Poisson geometry…
Inspired by recent works of Zang Liu, Alan Weinstein and Ping Xu, we introduce the notions of CC algebroids and non asymmetric Courant algebroids and study these structures. It is shown that CC algebroids of rank greater than 3 are the same as Courant algebroids up to a constant factor, though the definition of CC alge…
This note removes technical assumptions and characterizes relatively dominated representations.
problem Geometrically finiteness and Anosov conditions in higher-rank settings.
method Characterization using eigenvalue gaps and limit maps.
result Relatively dominated representations are characterized using eigenvalue gaps and limit maps.
Defines new two-variable elliptic genera for manifolds and derives modular forms.
problem Develops new elliptic genera for manifolds.
method Introduces and defines new two-variable elliptic genera for manifolds and derives their properties.
result Derives modular forms from the elliptic genera.
Study matches two noisy point clouds with geometric transformations and relabeling.
problem Matching two noisy point clouds with orthogonal transformations and relabeling.
method Information-theoretic results and Ping-Pong algorithm for computational alignment.
result The Ping-Pong algorithm retrieves the planted signal after one step.
Scalable web crawling using noisy change-indicating signals.
problem Optimizing web page freshness with limited bandwidth and noisy side information.
method Proposes a scalable crawling algorithm that uses noisy side information optimally.
result Achieves constant total rate of crawling without spikes in bandwidth usage.
Proposes tunable GMM kernels for classification tasks.
problem Lack of competitive performance of GMM kernels compared to tree methods on deep learning datasets.
method Introduces tunable GMM kernels with added parameters and combines basic kernels for improved performance.
result Tunable GMM kernels can produce good results for various classification tasks.
We study the geometry and dynamics of discrete infinite covolume subgroups of higher rank semisimple Lie groups. We introduce and prove the equivalence of several conditions, capturing "rank one behavior'' of discrete subgroups of higher rank Lie groups. They are direct generalizations of rank one equivalents to convex…
Researchers use FIR filters to predict COVID-19 infections and recoveries.
problem Predicting the spread of COVID-19 without a vaccine.
method Modified numerical method using FIR filters and ridge regression.
result Modified algorithm yields better approximation errors.
Teichmuller solved the type problem for Riemann surfaces.
problem Deciding if a Riemann surface is conformally equivalent to the complex plane or unit disc.
method Using line complexes and quasiconformal mappings, Teichmuller proved equivalence of surfaces with the same ramification measure.
result A simply connected Riemann surface is hyperbolic if sufficiently ramified.