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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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4895143190 · Jun 202019922001200920172026
48 results for RFRS groups

We describe a criterion for a real or complex hyperbolic lattice to admit a RFRS tower that consists entirely of congruence subgroups. We use this to show that certain Bianchi groups PSL(Od)\mathrm{PSL}(\mathcal{O}_d) are virtually fibered on congruence subgroups, and also exhibit the first examples of RFRS Kähler groups th…

2019-12-21abs ↗pdf ↗

In this article we develop the theory of residually finite rationally pp (RFRpp) groups, where pp is a prime. We first prove a series of results about the structure of finitely generated RFRpp groups (either for a single prime pp, or for infinitely many primes), including torsion-freeness, a Tits alternative, and …

2016-04-07abs ↗pdf ↗

Optimal AFs minimize RFR test error and sensitivity.

problem Finding optimal AFs for RFR to minimize test error and sensitivity.
method Closed-form solution for AFs minimizing test error and sensitivity under different functional parsimony.
result Optimal AFs can be linear, saturated linear, or Hermite polynomial expressions.

In 2007 Agol showed that if N is an aspherical compact 3-manifold with empty or toroidal boundary such that its fundamental group is virtually RFRS, then NN is virtually fibered. We give a largely self-contained proof of Agol's theorem using complexities of sutured manifolds.

2012-10-17abs ↗pdf ↗

We show that a finitely generated residually finite rationally solvable (or RFRS) group GG is virtually fibred, in the sense that it admits a virtual surjection to Z\mathbb{Z} with a finitely generated kernel, if and only if the first L2L^2-Betti number of GG vanishes. This generalises (and gives a new proof of) the…

2018-09-25abs ↗pdf ↗

We prove that an irreducible 3-manifold whose fundamental group satisfies a certain group-theoretic property called RFRS is virtually fibered. As a corollary, we show that 3-dimensional reflection orbifolds and arithmetic hyperbolic orbifolds defined by a quadratic form virtually fiber. These include the Seifert Weber …

2007-07-31abs ↗pdf ↗

New method optimizes hyperparameters for randomized algorithms like random feature regression.

problem Optimizing hyperparameters in randomized algorithms is challenging due to their stochastic nature.
method Introduced a random objective function and used ensemble Kalman inversion (EKI) for gradient-free optimization.
result Demonstrated successful optimization of hyperparameters in various randomized algorithms.

New groups found that don't virtually algebraically fiber, related to mapping class group orbits.

problem Existence of finite orbits for higher Prym representations of the mapping class group.
method Study of surface-by-surface and surface-by-free groups.
result Existence of free-by-free and free-by-surface groups that do not algebraically fiber.

This paper stems from the observation (arising from work of T. Delzant) that "most" Kähler groups virtually algebraically fiber, i.e. admit a finite index subgroup that maps onto Z\Bbb{Z} with finitely generated kernel. For the remaining ones, the Albanese dimension of all finite index subgroups is at most one, i.e. t…

2017-04-24abs ↗pdf ↗

Paper examines pricing and hedging for cross-currency swaps referencing backward-looking rates.

problem Pricing and hedging cross-currency swaps with backward-looking rates.
method Uses interest rate and currency futures for hedging, analyzes arbitrage-free multi-curve setting.
result Explicit pricing and hedging results for CCBS with backward-looking rates.

SRFRN accelerates image super-resolution using shallow residual units.

problem High computational complexity and time in deep learning image super-resolution.
method SRFRN uses a bicubic interpolated low-resolution image and residual representative units (RFR) for faster and more efficient high-resolution image reconstruction.
result SRFRN achieves superior performance and faster execution time compared to existing methods.

Study uses SAR data to estimate forest vegetation indices, improving monitoring of temperate forests.

problem Limitations of optical satellite data in monitoring forest ecosystems, especially due to atmospheric effects.
method Estimating four vegetation indices (LAI, FAPAR, EVI, NDVI) using multitemporal Sentinel-1 SAR and ancillary data.
result Accurate estimation of forest vegetation indices using SAR data, achieving high R2R^2 and low MAE values.

New link groups are derived from torus necklaces, connecting braid groups to reflection groups.

problem Understanding the relationship between braid groups and reflection groups.
method Constructing torus necklaces and linking them to braid groups of JJ-reflection groups.
result Link groups of torus necklaces are precisely braid groups of JJ-reflection groups, with meridians as braid reflections.

The study proves super-rigidity of Gromov's random monster group for various types of groups.

problem Super-rigidity of Gromov's random monster group in various group types.
method Proof of morphisms having finite image and introduction of hereditary super-rigidity.
result Gromov's random monster group has super-rigidity and hereditary super-rigidity with respect to certain groups.

We study the structure of the virtual braid group. It is shown that the virtual braid group is a semi--direct product of the virtual pure braid group and the symmetric group. Also, it is shown that the virtual pure braid group is a semi--direct product of free groups. From these results we obtain a normal form of words…

2004-07-23abs ↗pdf ↗

Virtual twin groups map to symmetric groups, revealing automorphism structure.

problem Understanding homomorphisms between virtual twin groups and symmetric groups.
method Using irreducible right-angled Coxeter groups and right-angled Artin groups.
result A complete description of homomorphisms between virtual twin groups and symmetric groups, including the structure of the automorphism group of VTnVT_n.

The study restricts groups in graph of groups structures.

problem Realizing groups as fundamental groups of graph of groups with restricted vertex groups.
method Analyzes restrictions on groups that can be realized and applies to manifold construction.
result Places constraints on groups that can be realized in graph of groups structures.

New Garside structures found for torus knot groups and related braid groups.

problem Finding Garside structures for torus knot groups and related braid groups.
method Introducing a new Garside monoid M(n,m)\mathcal{M}(n,m) for (n,m)(n,m)-torus knot groups and other braid groups.
result New Garside structures for (n,m)(n,m)-torus knot groups and related braid groups are constructed.

Logarithmic separation profile in hyperbolic groups shows hierarchical structure.

problem Understanding hierarchical structure in hyperbolic groups with logarithmic separation.
method Proving groups with logarithmic separation split over cyclic groups and providing counterexamples.
result Not all groups with hierarchical structure have logarithmic separation profile.

We describe a procedure for constructing a generalized Thompson group out of a family of groups that is equipped with what we call a cloning system. The previously known Thompson groups F, V, Vbr and Fbr arise from this procedure using, respectively, the systems of trivial groups, symmetric groups, braid groups and pur…

2014-05-21abs ↗pdf ↗

The study restricts normal subgroups of Kähler groups, proving specific cases and general restrictions.

problem Characterizing normal subgroups of Kähler groups.
method Analyzing embeddings and conjugation actions of surface groups and one-ended hyperbolic groups.
result Restrictions on normal subgroups of Kähler groups, including virtual direct products and surface group properties.

Study fundamental groups of geometric transformation groups using loop spaces.

problem Understanding fundamental groups of geometric transformation groups.
method Use differential forms on loop spaces to prove infinite fundamental groups.
result Proves infinite fundamental groups for specific geometric transformation groups.

We discuss dense embeddings of surface groups and fully residually free groups in topological groups. We show that a compact topological group contains a nonabelian dense free group of finite rank if and only if it contains a dense surface group. Also, we obtain a characterization of those Lie groups which admit a dens…

2006-02-27abs ↗pdf ↗

We exhibit a family of infinite, finitely-presented, nilpotent-by-abelian groups. Each member of this family is a solvable S-arithmetic group that is related to Baumslag-Solitar groups, and everyone of these groups has a quasi-isometry group that is virtually a product of a solvable real Lie group and a solvable p-adic…

2005-07-09abs ↗pdf ↗