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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.

168,742 papers · 148 categories

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114228341455 · Jun 202019922001200920172026
48 results for polytopal complexes

Real moment-angle manifolds of combinatorially equivalent simple polytopes are equivariantly diffeomorphic.

problem Uniqueness of smooth structures on real moment-angle manifolds.
method Arguments from calculus applied to results from complex moment-angle manifolds.
result Real moment-angle manifolds of combinatorially equivalent simple polytopes are equivariantly diffeomorphic.

The study examines the topology of complements of polytopal skeletons.

problem Characterizing topological properties of polytopal complexes and their skeletons.
method Constructing a long exact sequence relating homologies of skeleton complements and links of faces.
result Characterizations of Cohen-Macaulay and Leray complexes, stacked balls, and neighbourly spheres in terms of skeleton complements.

The purpose of this thesis is to study classical combinatorial objects, such as polytopes, polytopal complexes, and subspace arrangements, using tools that have been developed in combinatorial topology, especially those tools developed in connection with (discrete) differential geometry, geometric group theory and low-…

2014-03-11abs ↗pdf ↗

In this paper we study a new combinatorial invariant of simple polytopes, which comes from toric topology. With each simple n-polytope P with m facets we can associate a moment-angle complex Z_P with a canonical action of the torus T^m. Then s(P) is the maximal dimension of a toric subgroup that acts freely on Z_P. The…

2009-08-24abs ↗pdf ↗

Generalizes Delzant theorem for torus-equivariantly embedded toric hypersurfaces.

problem Conditions for nonsingularity of complex subtorus orbits in symplectic toric manifolds.
method Clarification of Delzant theorem conditions using polytopes.
result Generalization of Delzant theorem for torus-equivariantly embedded toric hypersurfaces.

We call complex quasifold of dimension k a space that is locally isomorphic to the quotient of an open subset of the space C^k by the holomorphic action of a discrete group; the analogue of a complex torus in this setting is called a complex quasitorus. We associate to each simple polytope, rational or not, a family of…

2000-04-11abs ↗pdf ↗

The paper constructs submanifolds with corners in Delzant polytopes from affine subspaces.

problem Understanding submanifolds with corners in Delzant polytopes.
method Constructing submanifolds with corners in Delzant polytopes from affine subspaces.
result Conditions for submanifolds with corners are equivalent to those for torus-equivariantly embedded toric manifolds.

We use Fox calculus to assign a marked polytope to a `nice' group presentation with two generators and one relator. Relating the marked vertices to Novikov-Sikorav homology we show that they determine the Bieri-Neumann-Strebel invariant of the group. Furthermore we show that in many cases the marked polytope is an inva…

2015-01-14abs ↗pdf ↗

We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This involves constructing explicit complete acyclic Morse matchings on the face lattice of…

2011-07-25abs ↗pdf ↗

We investigate polyhedral 2k2k-manifolds as subcomplexes of the boundary complex of a regular polytope. We call such a subcomplex {\it kk-Hamiltonian} if it contains the full kk-skeleton of the polytope. Since the case of the cube is well known and since the case of a simplex was also previously studied (these are so…

2008-09-24abs ↗pdf ↗

In this paper, we investigate the topology of a class of non-Kähler compact complex manifolds generalizing that of Hopf and Calabi-Eckmann manifolds. These manifolds are diffeomorphic to special systems of real quadrics in Cn\Bbb C^n which are invariant with respect to the natural action of the real torus $(\Bbb S^1)^n…

2004-05-05abs ↗pdf ↗

The paper provides conditions for realizing graphs and polytopes with specified edge lengths.

problem Proving the existence of planar embeddings or polyhedra with specified edge lengths.
method Practical sufficient conditions and software verification for non-self-intersecting perturbations of initial realizations.
result Existence of planar embeddings and polyhedra with specified edge lengths.

In the classical theory of toric manifolds polytopes appear in two guises -- as Newton polytopes of line bundles on the complex, and as moment polytopes on the symplectic side, the link between the two being established by the prequantizability condition on the cohomology class of the symplectic form. Here we give a co…

2017-02-08abs ↗pdf ↗

In this paper we shall illustrate that each polytopal moment-angle complex can be understood as the intersection of the minima of corresponding Siegel leaves and the unit sphere, with respect to the maximum norm. Consequently, an alternative proof of a rigidity theorem of Bosio and Meersseman is obtained; as piecewise …

2014-04-06abs ↗pdf ↗

Tree complex linked to polyhedral shapes like associahedra and cyclohedra.

problem Understanding the structure of mapping class groups and complex dynamics.
method Characterizing associahedra and cyclohedra using planar tree embeddings and barycentric subdivision.
result Tree complex is a barycentric subdivision of a polyhedral cell complex made of associahedra and cyclohedra.

Chow stability is one notion of Mumford's Geometric Invariant Theory for studying the moduli space of polarized varieties. Kapranov, Sturmfels and Zelevinsky detected that Chow stability of polarized toric varieties is determined by its inherent {\it secondary polytope}, which is a polytope whose vertices correspond to…

2013-06-19abs ↗pdf ↗

Unified approach to verify NN properties using ReLU's unique polytope structure.

problem Lack of robustness and interpretability in ReLU NNs for risk-sensitive applications.
method Identifying and traversing the local polytopes of ReLU NNs, developing an algorithm to verify properties.
result Unified approach to examine network behavior in risk-sensitive settings.

Given an L2L^2-acyclic connected finite CWCW-complex, we define its universal L2L^2-torsion in terms of the chain complex of its universal covering. It takes values in the weak Whitehead group Whw(G)\operatorname{Wh}^w(G). We study its main properties such as homotopy invariance, sum formula, product formula and Poincaré d…

2016-09-25abs ↗pdf ↗

The study broadens the concept of cyclic polytopes to Veronese polytopes.

problem Extending the framework of cyclic polytopes to a broader class of polytopes.
method Described facial structure and combinatorial characterisation of facets via σ-parity alternating sequences.
result Established a bijective correspondence between combinatorial types of Veronese polytopes and partitions of finite sets.

Consider a Hamiltonian action of a compact Lie group on a compact symplectic manifold. A theorem of Kirwan's says that the image of the momentum mapping intersects the positive Weyl chamber in a convex polytope. I present a new proof of Kirwan's theorem, which gives explicit information on how the vertices of the polyt…

1994-08-15abs ↗pdf ↗

The Thurston norm is derived from polytopes and applied to group cohomology.

problem Understanding the structure of finitely generated torsion-free groups.
method Using the Strong Atiyah Conjecture and L2L^2-Betti numbers, the Thurston norm is defined and related to polytopes.
result The Thurston norm is a seminorm on the first cohomology group of a group with real coefficients.

In 1976 Thurston associated to a 33-manifold NN a marked polytope in H1(N;R),H_1(N;\mathbb{R}), which measures the minimal complexity of surfaces representing homology classes and determines all fibered classes in H1(N;R)H^1(N;\mathbb{R}). Recently the first and the last author associated to a presentation ππ with two generato…

2015-07-20abs ↗pdf ↗

The paper studies deformation spaces of Coxeter truncation polytopes.

problem Understanding the geometric properties and deformations of Coxeter truncation polytopes.
method Analyzing Coxeter truncation polytopes and their deformation spaces.
result Description of deformation spaces for Coxeter truncation polytopes of dimension d4d \geqslant 4.

Constructs combinatorial 2D topological field theories from cyclic A-infinity algebras.

problem Developing a combinatorial framework for 2D topological field theories.
method Using triangulations and polygonal decompositions, constructing cochains on a CW complex.
result Existence of combinatorial 2D topological field theories based on cyclic A-infinity algebras.

We introduce the geodesic walk for sampling Riemannian manifolds and apply it to the problem of generating uniform random points from polytopes in R^n specified by m inequalities. The walk is a discrete-time simulation of a stochastic differential equation (SDE) on the Riemannian manifold equipped with the metric induc…

2016-06-15abs ↗pdf ↗

Given a finite collection P of convex n-polytopes in RP^n (n>1), we consider a real projective manifold M which is obtained by gluing together the polytopes in P along their facets in such a way that the union of any two adjacent polytopes sharing a common facet is convex. We prove that the real projective structure on…

2007-05-27abs ↗pdf ↗

Average teaching complexity for locating target regions among halfspace intersections is Θ(d).

problem Teaching the location of a target region among intersections of halfspaces.
method Novel insights from computational geometry to count convex polytopes and faces.
result Average-case teaching complexity is Θ(d), contrasting with Θ(n) worst-case complexity.

Given a lattice L of R^n, a polytope D is called a Delaunay polytope in L if the set of its vertices is S\cap L where S is a sphere having no lattice points in its interior. D is called perfect if the only ellipsoid in R^n that contains S\cap L is exactly S. For a vector v of the Leech lattice Λ_{24} we define Λ_{24}(v…

2009-07-04abs ↗pdf ↗

Polytopic Matrix Factorization models data as latent vectors from a polytope, maximizing determinant for identifiability.

problem Data decomposition with semi-structured latent vectors and polytope constraints.
method Model input data as latent vectors from a polytope, using determinant maximization for identifiability.
result Identifiability condition for polytopes with specific symmetry restrictions.

The article studies factorization structures in geometry and their applications to cones and polytopes.

problem Understanding and characterizing factorization structures in geometry.
method Comprehensive study of factorization structures, including structure theory, construction of compatible polytopes and cones, and derivation of generalised Gale's evenness condition.
result Established generalised Vandermonde identities and found examples of Delzant and rational Delzant compatible polytopes.

New methods classify hyperbolic polytopes with up to 40 facets.

problem Classifying compact hyperbolic Coxeter polytopes with specific facet counts.
method New combinatorial method via point set order types.
result Proves existence of a compact hyperbolic Coxeter 29-polytope with at least 40 facets.