arXiv research

Paper tackles infinite action linear bandits with tight regret bounds.

The paper extends Thompson Sampling to infinite action spaces using information theory.

Study quotients of curve complex actions by mapping class group.

Extends quantum annular homology to infinite sets.

VC dimensions of group CNNs are infinite for certain kernels and groups.

New braid group actions on $n$-adic integers linked to real algebraic links.

Bayesian algorithms improve online learning with adversaries over infinite action spaces.

New findings on group actions and stabilizers of infinite sets.

Ellipsoids host infinitely many minimal tori, bifurcating from a 2-torus orbit.

Constructs infinitely many non-equivalent wild knots in Menger sponge.

Consider a hyperbolic group G and a quasiconvex subgroup H of infinite index. We construct a set-theoretic section s of the quotient map (of sets) from G to G/H such that s(G/H) is a net in G; that is, any element of G is a bounded distance from s(G/H). This section arises naturally as a set of points minimizing word-l…

Study tackles OPE in confounded settings, estimating policy value from proxies.

We study discrete, cocompact, isometric actions of groups on Hadamard spaces, and the induced actions on ideal boundaries. For a class of groups generalizing fundamental groups of three-dimensional graph manifolds, we find a set of invariants for the action which determine the boundary action up to equivariant homeomor…

Let $ρ_0$ be an action of a Lie group on a manifold with boundary that is transitive on the interior. We study the set of actions that are topologically conjugate to $ρ_0$, up to smooth or analytic change of coordinates. We show that in many cases, including the compactifications of negatively curved symmetric spaces, …

Study infinite dimensional Lie algebras and their Poisson structures from Lie group actions.

We define a Toledo number for actions of surface groups and complex hyperbolic lattices on infinite dimensional Hermitian symmetric spaces, which allows us to define maximal representations. When the target is not of tube type we show that there cannot be Zariski-dense maximal representations, and whenever the existenc…

The paper finds infinite families of exotic spheres with free actions.

In this paper we prove several related results concerning smooth $\Z_p$ or $\s^1$ actions on 4-manifolds. We show that there exists an infinite sequence of smooth 4-manifolds $X_n$, $n\geq 2$, which have the same integral homology and intersection form and the same Seiberg-Witten invariant, such that each $X_n$ support…

Meta-algorithm optimizes nonstochastic bandits with infinitely many experts.

Investigates sequential problems on graph structures and large action spaces.

We study when the mapping class group of an infinite-type surface $S$ admits an action with unbounded orbits on a connected graph whose vertices are simple closed curves on $S$. We introduce a topological invariant for infinite-type surfaces that determines in many cases whether there is such an action. This allows us …

Smooth actions of infinite groups linked to homotopy theory.

Study mapping class groups of infinite type surfaces, classify loxodromic elements, and prove infinite-dimensional cohomology.

New representation of PSL2(R) on infinite hyperbolic space via convex bodies.

New algorithm tracks changes in infinite action space rewards.

Study bounds and asymptotic behavior of largest purely non-free actions on compact Riemann surfaces.

In this paper we explore the geometry and topology of cohomogeneity one manifolds, i.e. manifolds with a group action whose principal orbits are hypersurfaces. We show that the principal group action of every principal SO(3) and SO(4) bundle over S^4 extends to a cohomogeneity one action. As a consequence we prove that…

There are known infinite families of Brieskorn homology 3-spheres which can be realized as boundaries of smooth contractible 4-manifolds. In this paper we show that free periodic actions on these Brieskorn spheres do not extend smoothly over a contractible 4-manifold. We give a new infinite family of examples in which …

Consider the cyclic group C_2 of order two acting by complex-conjugation on the unit circle S^1. The main result is that a finitely dominated manifold W of dimension > 4 admits a cocompact, free, discontinuous action by the infinite dihedral group D_\infty if and only if W is the infinite cyclic cover of a free C_2-man…

We establish a general slice theorem for the action of a locally convex Lie group on a locally convex manifold, which generalizes the classical slice theorem of Palais to infinite dimensions. We discuss two important settings under which the assumptions of this theorem are fulfilled. First, using Glöckner's inverse fun…

Infinite 2-groups of bounded exponent cannot act faithfully on compact manifolds.

Two results on end spaces of infinite type surfaces, answering questions about their topology and equivalence.

Probabilistic model for exhaustion in infinite-genus curve complexes.

The paper explores smooth equivariant rigidity and finds infinitely many exotic smooth structures.

New algorithm for Q-learning in MDPs with infinite states and actions.

Motivated by the recent applications of game-theoretical learning techniques to the design of distributed control systems, we study a class of control problems that can be formulated as potential games with continuous action sets, and we propose an actor-critic reinforcement learning algorithm that provably converges t…

Smooth and symplectic symmetries of an infinite family of distinct exotic $K3$ surfaces are studied, and comparison with the corresponding symmetries of the standard $K3$ is made. The action on the $K3$ lattice induced by a smooth finite group action is shown to be strongly restricted, and as a result, nonsmoothability…

We construct finitely generated groups with strong fixed point properties. Let $\mathcal{X}_{ac}$ be the class of Hausdorff spaces of finite covering dimension which are mod-$p$ acyclic for at least one prime $p$. We produce the first examples of infinite finitely generated groups $Q$ with the property that for any act…

We show that for $X$ a proper $\mathrm{CAT}(-1)$ space there is a maximal open subset of the horofunction compactification of $X\times X$ with respect to the maximum metric that compactifies the diagonal action of an infinite quasi-convex group of the isometries of $X$. We also consider the product action of two quasi-…

Study groups acting on trees with specific local actions, proving cohomology vanishing or infinite.

The study embeds infinite-dimensional geometric structures in Cayley graphs.

In this article we study properly discontinuous actions on Hilbert manifolds giving new examples of complete Hilbert manifolds with nonnegative, respectively nonpositive, sectional curvature with infinite fundamental group. We also get examples of complete infinite dimensional Kähler manifolds with positive holomorphic…

We prove the following well known conjecture: let $Σ$ be an oriented surface of finite type whose fundamental group is a nonabelian free group. Let $φ\in \textup{Mod}(Σ)$ be a an infinite order mapping class. Then there exists a finite solvable cover $\widehatΣ \to Σ$, and a lift $\widehatφ$ of $φ$ such that the action…

Proves convergence of normal forms for infinite-dimensional Lie pseudo-group actions.

Study sparsity benefits in infinite feature contextual bandits.

Study classifies mapping class groups with hyperbolic actions on infinite-type surfaces.

The mapping class group $Γ$ of the complement of a Cantor set in the plane arises naturally in dynamics. We show that the ray graph, which is the analog of the complex of curves for this surface of infinite type, has infinite diameter and is hyperbolic. We use the action of $Γ$ on this graph to find an explicit non tri…

I give a construction of compact group action on a finite dimensional space Y, whose orbit space is infinite dimensional.