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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.

168,695 papers · 148 categories

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176352527703 · Jun 202019922001200920172026
48 results for Complex points

Paper finds at least 6 fixed points for a specific circle action on a 10D manifold.

problem Finding the minimum number of fixed points for a circle action on a 10D almost complex manifold.
method Established a lower bound by showing the non-existence of a circle action with 4 fixed points.
result There are at least 6 fixed points for a circle action on a 10D compact almost complex manifold.

In this note, we investigate the relation between double points and complex points of immersed surfaces in almost-complex 4-manifolds and show how estimates for the minimal genus of embedded surfaces lead to inequalities between the number of double points and the number of complex points of an immersion. We also provi…

2000-08-31abs ↗pdf ↗

Study fixed-point sets of S1S^{1}-actions on quaternionic manifolds.

problem Characterize fixed-point sets and compatible complex structures on quaternionic manifolds.
method Analyze fixed-point sets and derive equations involving first Chern classes.
result Conditions for the existence of hypercomplex structures on quaternionic manifolds.

The article applies Lusternik-Schnirelmann theory to establish lower bounds on critical points using sequential and parametrized topological complexity.

problem Establishing lower bounds on the number of critical points of functions using topological complexity.
method Applying Lusternik-Schnirelmann theory to sequential and parametrized topological complexity.
result Established various lower bounds on the number of critical points using sequential and parametrized topological complexity.

The author proved that if the circle acts symplectically on a compact, connected symplectic manifold MM with three fixed points, then MM is equivariantly symplectomorphic to some standard action on CP2\mathbb{CP}^2. In this paper, we extend the result to a circle action on an almost complex manifold; if the circle act…

2015-10-04abs ↗pdf ↗

The study examines higher-order modern portfolio theory with complex critical points and feasible portfolio variety.

problem Understanding the complex critical points and feasible portfolio variety in higher-order modern portfolio theory.
method Established genericity conditions for utility functions with higher-order cumulants, analyzed discriminant loci, and determined the dimension and degree of the feasible portfolio variety.
result The utility function has a constant number of complex critical points under genericity conditions, and the feasible portfolio variety has a determined dimension and degree.

This paper tackles the computational complexity of finding approximate stationary points in non-convex optimization.

problem Finding approximate stationary points in non-convex optimization problems.
method PLS-completeness, zero-order algorithms, and gradient queries.
result The query complexity of finding approximate stationary points is Θ(1/ε) for d=2.

Conditions for hyperbolic and relatively hyperbolic extensions of free groups using automorphisms with fixed points.

problem Conditions for hyperbolic and relatively hyperbolic extensions of free groups.
method Using dynamics of outer automorphisms on the complex of free factors and investigating the geometry of the extension group.
result Conditions for hyperbolic and relatively hyperbolic extensions of free groups using automorphisms with fixed points.

Fix a finite set of points in Euclidean nn-space $\euc^n$, thought of as a point-cloud sampling of a certain domain $D\subset\euc^n$. The Rips complex is a combinatorial simplicial complex based on proximity of neighbors that serves as an easily-computed but high-dimensional approximation to the homotopy type of DD. …

2007-12-03abs ↗pdf ↗

The paper tackles efficient change point detection with limited samples.

problem Identifying multiple change points with minimal queries in noisy environments.
method Adaptive algorithm that first detects likely change points and refines their locations.
result The sample complexity is jointly governed by jump magnitudes and change point positions.

New method finds stationary points in bilevel optimization problems.

problem Solving nonconvex-strongly-convex bilevel optimization problems.
method Restarted Accelerated HyperGradient Descent (RAHGD) method.
result Achieves best-known theoretical guarantees for finding stationary points in bilevel optimization.

A topological invariant of a polynomial map p:XBp:X\to B from a complex surface containing a curve CXC\subset X to a one-dimensional base is given by a rational second homology class in the compactification of the moduli space of genus gg curves with nn labeled points $\modmgn$. Here the generic fibre of pp has genus …

2006-05-10abs ↗pdf ↗

Paper introduces a neural network-based non-stationary influence kernel for complex event data.

problem Modeling complex, non-stationary, and dependent discrete event data.
method Neural Spectral Marked Point Processes (NSMPP) with a versatile non-stationary influence kernel.
result NSMPP outperforms state-of-the-art models on synthetic and real data.

Research examines correlations of complex logarithms of lattice points, showing level repulsion and Poissonian behavior.

problem Analyzing correlations of complex logarithms of lattice points.
method Proving existence of pair correlation functions and examining behavior at various scalings.
result Level repulsion observed at linear scaling, Poissonian behavior at sublinear scalings.

We describe the fundamental groups of ordered and unordered k point sets in complex projective space of dimension n generating a projective subspace of dimension i. We apply these to study connectivity of more complicated configurations of points.

2010-02-11abs ↗pdf ↗

We address the problem of existence and uniqueness of a Levi-flat hypersurface MM in CnC^n with prescribed compact boundary SS for n3n\ge3. The situation for n3n\ge3 differs sharply from the well studied case n=2n=2. We first establish necessary conditions on SS at both complex and CR points, needed for the existence…

2009-04-02abs ↗pdf ↗

The paper studies almost complex torus manifolds using graphs and Hirzebruch genera, proving properties of their fixed points and cohomology.

problem Understanding the fixed points and cohomology of almost complex torus manifolds.
method Using directed labeled multigraphs and Hirzebruch genera to encode and analyze the manifolds.
result Almost complex torus manifolds have positive Todd genus and at least n+1 fixed points.

GOCPD detects change points by maximizing the probability of two independent models.

problem Large false discovery rates in online change point detection methods.
method GOCPD uses ternary search to find change points by maximizing the probability of two independent models.
result GOCPD accelerates CPD with logarithmic complexity for single change point detection.

The braid group of a complex reflection group is shown to be an index d subgroup.

problem Understanding the structure of braid groups associated with complex reflection groups.
method Presented a compatible presentation for the braid group of the orbifold quotient and a tagged triangulation of the disk.
result The braid group of the complex reflection group G(d,d,n)G(d,d,n) is an index dd subgroup of the braid group of the orbifold quotient.

Kakimizu complex of a knot is a flag simplicial complex whose vertices correspond to minimal genus Seifert surfaces and edges to disjoint pairs of such surfaces. We discuss a general setting in which one can define a similar complex. We prove that this complex is contractible, which was conjectured by Kakimizu. More ge…

2010-04-23abs ↗pdf ↗

Improved DP optimization for nonconvex, nonsmooth objectives with reduced sample complexity.

problem Differentially private optimization of nonconvex, nonsmooth objectives.
method Proposes single-pass and multi-pass DP algorithms with improved sample complexity.
result Sample complexity bounds improved by factors of Ω(d)Ω(\sqrt{d}) and Ω(d3/4)Ω(d^{3/4}).

We give nearly matching upper and lower bounds on the oracle complexity of finding εε-stationary points (F(x)ε\| \nabla F(x) \| \leqε) in stochastic convex optimization. We jointly analyze the oracle complexity in both the local stochastic oracle model and the global oracle (or, statistical learning) model. This allows u…

2019-02-13abs ↗pdf ↗

We apply fixed-point techniques to compute the coefficient ring of semifree geometric circle-equivariant complex cobordism with isolated fixed points, recovering a 2004 result of Sinha through 19th-century methods.

2019-08-19abs ↗pdf ↗

We prove that the half-integer valued local index of an isolated umbilic point on a C3+αC^{3+α}-smooth convex surface in Euclidean 3-space is less than two. The approach is to study the co-kernel of an associated Riemann-Hilbert boundary value problem. The link between the local and global is a semi-local technique that …

2012-07-25abs ↗pdf ↗

We apply the methods of Heegaard Floer homology to identify topological properties of complex curves in the complex projective plane. As one application, we resolve an open conjecture that constrains the Alexander polynomial of the link of the singular point of the curve in the case that there is exactly one singular p…

2013-04-03abs ↗pdf ↗

For a G-invariant holomorphic 1-form with an isolated singular point on a germ of a complex-analytic G-variety with an isolated singular point (G is a finite group) one has notions of the equivariant homological index and of the (reduced) equivariant radial index as elements of the ring of complex representations of th…

2017-01-07abs ↗pdf ↗

For any compact, connected, orientable, finite-type surface with marked points other than the sphere with three marked points, we construct a finite rigid set of its arc complex: a finite simplicial subcomplex of its arc complex such that any locally injective map of this set into the arc complex of another surface wit…

2019-09-19abs ↗pdf ↗

Paper introduces Chern minimal surfaces in Hermitian surfaces and establishes identities related to their points and bundles.

problem Understanding the properties of Chern minimal surfaces in Hermitian surfaces.
method Using the Chern connection, the paper introduces Chern minimal surfaces and establishes identities related to their points and bundles.
result Established two identities relating the orders of complex and anticomplex points, the cap product of pull-back of first Chern class, and the Euler characteristics of tangent and normal bundles.