Research
On-device research index

arXiv research

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.

168,742 papers · 148 categories

Trend · papers per month

4182122163 · May 202619922001200920172026
48 results for Invariant subspaces

In this paper we consider the problem of group invariant subspace clustering where the data is assumed to come from a union of group-invariant subspaces of a vector space, i.e. subspaces which are invariant with respect to action of a given group. Algebraically, such group-invariant subspaces are also referred to as su…

2015-10-15abs ↗pdf ↗

The Grassmannian model represents harmonic maps from Riemann surfaces by families of shift-invariant subspaces of a Hilbert space. We impose a natural symmetry condition on the shift-invariant subspaces that corresponds to considering an important class of harmonic maps into symmetric and kk-symmetric spaces. In parti…

2019-08-05abs ↗pdf ↗

Study non-asymptotic bounds on correlation in high-dimensional linear systems, revealing invariant subspaces and bottlenecks.

problem Understanding correlation and mixing in high-dimensional linear systems with Gaussian noise.
method Sampling from sub-trajectories, using Talagrand's inequality, and analyzing invariant subspaces.
result Large discrepancy between algebraic and geometric multiplicity leads to bottlenecks between invariant subspaces.

In the paper we consider the theory of elliptic operators acting in subspaces defined by pseudodifferential projections. This theory on closed manifolds is connected with the theory of boundary value problems for operators violating Atiyah-Bott condition. We prove an index formula for elliptic operators in subspaces de…

1999-07-06abs ↗pdf ↗

Proposes a new algorithm to estimate invariant subspaces across multilayer networks.

problem Estimating invariant subspaces across heterogeneous multiple networks.
method Bias-corrected joint spectral embedding algorithm that recursively calibrates diagonal bias and iteratively updates the subspace estimator.
result Established entrywise subspace perturbation bound and entrywise eigenvector central limit theorem for the algorithm.

Study Sp(n)Sp(n)-orbits in complex and ΣΣ-complex subspaces of Hermitian quaternionic vector spaces.

problem Characterize Sp(n)Sp(n)-orbits in Grassmannians of complex and ΣΣ-complex subspaces.
method Decompose subspaces into 4-dimensional complex addends and 2-dimensional totally complex subspace. Use properties of isoclinic subspaces and principal angles.
result Determine full set of invariants for Sp(n)Sp(n)-orbits in GrR(2k,4n)Gr^\R(2k,4n).

This paper improves Koopman operator approximations by pruning subspaces in RKHS.

problem Improving predictive accuracy of Koopman operator approximations.
method Computes principal angles and vectors in RKHS to prune subspaces.
result Validated approach enhances Koopman operator approximations for large datasets.

An elliptic theory is constructed for operators acting in subspaces defined via odd pseudodifferential projections. Subspaces of this type arise as Calderon subspaces for first order elliptic differential operators on manifolds with boundary, or as spectral subspaces for self-adjoint elliptic differential operators of …

1999-07-07abs ↗pdf ↗

The paper extends hypothesis testing to non-diagonalizable matrices, improving network statistics inference.

problem Testing on non-diagonalizable matrices for network statistics.
method Generalizes Wald and t-tests to non-symmetric matrices, controlling convergence rates.
result Improved inference on network statistics from directed networks.

For a Veech surface (x,ω), we characterize subspaces of X^n, invariant under the diagonal action of the affine group of X. We prove that non-arithmetic Veech surfaces have only finitely many invariant subspaces of very particular shape (in any dimension). Among other consequences we find copies of (X,ω) embedded in the…

2006-02-17abs ↗pdf ↗

The spectral eta-invariant of a self-adjoint elliptic differential operator on a closed manifold is rigid, provided that the parity of the order is opposite to the parity of dimension of the manifold. The paper deals with the calculation of the fractional part of the eta-invariant in this case. The method used to obtai…

1999-07-08abs ↗pdf ↗

The paper studies the n-loop Kontsevich invariant of knots with same Alexander polynomial.

problem Understanding the n-loop Kontsevich invariant for knots with identical Alexander polynomials.
method Analyzes the subspace generated by the n-loop Kontsevich invariant of knots with genus ≤ g and same Alexander polynomial.
result For n ≥ 2, the subspace is finite-dimensional.

We study the geometry of an important class of generic curves in the Grassmannian manifolds of nn-dimensional subspaces and Lagrangian subspaces of R2nR^{2n} under the action of the linear and linear symplectic group.

2005-02-23abs ↗pdf ↗

We investigate in detail the connection between harmonic maps from Riemann surfaces into the unitary group $\U(n)$ and their Grassmannian models: these are families of shift-invariant subspaces of $L^2(S^1,\C^n)$. With the help of operator-theoretic methods we derive a criterion for finiteness of the uniton number whic…

2018-12-21abs ↗pdf ↗

Study analyzes perturbations in singular subspaces under random noise.

problem Understanding singular vector and subspace changes in signal-plus-noise models.
method Generalized Davis-Kahan-Wedin theorem for any unitarily invariant norm, considering \ell_\infty and 2,\ell_{2,\infty} bounds.
result Fine-grained insights into singular vector and subspace perturbations, including \ell_\infty and 2,\ell_{2,\infty} bounds.

We give a complete description of all order 1 invariants of spherical curves. We also identify the subspaces of all J-invariants and S-invariants, and present two equalities satisfied by any spherical curve.

2007-10-10abs ↗pdf ↗

Extends Kähler metrics theory to symplectic manifolds with toric actions.

problem Extending invariant Kähler metrics theory to symplectic manifolds with toric actions.
method Using Delzant subspaces and Lagrangian fibrations, establishing a correspondence between metrics and connections.
result Characterizes extremal invariant Kähler metrics as those with scalar curvature on base integral affine manifold.

Study Sp(n)Sp(n)-orbits of isoclinic subspaces in real Grassmannians.

problem Understanding Sp(n)Sp(n)-orbits of isoclinic subspaces in real Grassmannians.
method Investigate isoclinic subspaces in GR(k,4n)G^\R(k,4n) using Hermitian quaternionic structure and admissible hypercomplex basis.
result Angles of isoclinicity and invariants (ξ,χ,η,Δ)(ξ,χ,η, Δ) determine Sp(n)Sp(n)-orbit of isoclinic subspaces.

We study the isotropy representation of real flag manifolds associated to simple Lie algebras that are split real forms of complex simple Lie algebras. For each Dynkin diagram the invariant irreducible subspaces for the compact part of the isotropy subgroup are described. Contrary to the complex flag manifolds the deco…

2014-05-26abs ↗pdf ↗

In this article we study Whitney (B) regular stratified spaces with the action of a compact Lie group GG which preserves the strata. We prove an equivariant submersion theorem and use it to show that such a GG-stratified space carries a system of GG-equivariant control data. As an application, we show that if $A \su…

2017-06-29abs ↗pdf ↗

Study geometric inequalities for CR-submanifolds using curvature invariants.

problem Geometric inequalities for CR-submanifolds in almost Hermitian spaces.
method Comparing mutual curvature invariants with Chen-type invariants and proving geometric inequalities.
result Proved geometric inequalities with intermediate mean curvature squared for CR-submanifolds.

Minimal orbits of semi-simple Lie groups are studied and related to invariant subspaces.

problem Characterizing minimal orbits of semi-simple Lie groups.
method Analyzing projective orbits induced by representations of semi-simple Lie groups and relating them to invariant subspaces of the underlying modules.
result Minimal orbits of semi-simple Lie groups are in bijection with minimal orbits of compact subgroups on invariant subspaces.

The paper explores subspaces in hyperbolic lattices and their arithmetic properties.

problem Arithmeticity criterion for hyperbolic lattices and suborbifolds.
method Analysis of totally geodesic suborbifolds and Vinberg's commensurability invariants.
result Arithmeticity of hyperbolic orbifolds is linked to the existence of infinitely many fc-subspaces.

New algorithms extract Koopman invariant subspaces from large-scale data.

problem Difficulty in discerning the Koopman invariant subspace from many Koopman eigenmodes.
method Multi-task feature learning and pruning procedure to remove spurious modes.
result Effective in approximating Koopman operator for complex flows.

Researchers classify and decompose valuations on convex functions.

problem Classifying valuations on convex functions.
method Geometric decomposition of valuations, using properties of special subspaces and Monge-Ampère-type operators.
result Valuations decompose into subspaces defined by vanishing properties.

A new method for spectral positional encodings in directed graphs using Hermitian block Krylov subspaces.

problem Challenges in spectral positional encodings for directed graphs, including computational complexity and gauge invariance issues.
method Learnable spectral positional encodings of the form hθ(Aq)Rh_θ(A_q)R, computed in a Hermitian block Krylov subspace from sparse matrix-vector products.
result The method is gauge-invariant and converges to the exact eigendecomposition oracle as the depth grows.

We study the geometry of fanning curves in the Grassmann manifold of n-dimensional subspaces of Rkn\mathbb{R}^{kn}; we construct a complete system of invariants which solve the congruence problem. The geometry of the invariants themselves and their relation with classical invariants is also studied.

2014-12-10abs ↗pdf ↗

Study finds abnormal paths on specific Lie groups using algebraic structures.

problem Identifying abnormal extremals on Lie groups with quasimetrics.
method Analyzing Lie algebras and seminorms to determine abnormal extremals.
result Established criterion for strong abnormality of extremals.

We discuss an "extrinsic" property of knots in a 3-subspace of the 3-sphere S3S^3 to characterize how the subspace is embedded in S3S^3. Specifically, we show that every knot in a subspace of the 3-sphere is transient if and only if the exterior of the subspace is a disjoint union of handlebodies, i.e. regular neighbor…

2015-02-17abs ↗pdf ↗

We study the structure group of a canonical algebraic curvature tensor built from a symmetric bilinear form, and show that in most cases it coincides with the isometry group of the symmetric form from which it is built. Our main result is that the structure group of the direct sum of such canonical algebraic curvature …

2011-08-10abs ↗pdf ↗

Paper tackles distribution shifts in prediction models with unobserved confounding.

problem Distribution shifts in prediction models with unobserved confounding.
method Linear structural causal model, invariant covariate representations, data-driven representation learning method.
result Optimizes for a lower-dimensional linear subspace and a prediction model confined to that subspace, achieving nearly ideal gap between target and source risk.

The study examines algebraic structures of specific tensor forms in four-dimensional spacetimes.

problem Investigating algebraic features of certain tensor forms in spacetimes.
method General treatment followed by specialization to four-dimensional spacetimes, focusing on invariant subspaces and generalizing relations.
result Generalized relations such as the Ruse-Lanczos identity, Bel-Matte decomposition, and Lovelock-like quadratic identities.

Paper proposes distributed sparse multicategory discriminant analysis for classification.

problem Sparse multicategory classification with distributed data.
method Convex formulation, distributed setting, invariant discriminant subspace recovery.
result Distributed sparse multicategory linear discriminant analysis performs as good as centralized version after a few rounds of communications.

New cyclicity measures defined in weighted Besov spaces, with stability and geometric analysis.

problem Characterizing cyclicity in weighted Besov spaces.
method Defining cyclicity indices based on potential theory and capacity, studying stability under perturbations, and linking zero set structure to cyclicity.
result Novel invariants and conditions for cyclicity in various function spaces.

We classify the holonomy algebras of manifolds admitting an indecomposable torsion free G2G_2^*-structure, i.e. for which the holonomy representation does not leave invariant any proper non-degenerate subspace. We realize some of these Lie algebras as holonomy algebras of left-invariant metrics on Lie groups.

2016-04-02abs ↗pdf ↗