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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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4.2%8.3%12.5%16.7% · Sep 199519922001200920172026
48 results for gradient-like flows

Gradient-like flows on certain manifolds restrict saddle Morse indices to 1 or n-1.

problem Restricting Morse indices of saddles in gradient-like flows.
method Analyzing invariant manifolds and their intersections for gradient-like flows.
result Morse indices of saddles are either 1 or n-1, no other indices possible.

Study homotopy equivalence of spaces of gradient-like flows and Morse functions on surfaces.

problem Understanding the topology of spaces of smooth functions and flows on surfaces.
method Proves homotopy equivalence of spaces of gradient-like flows and Morse functions on surfaces, with detailed decomposition into orbits.
result Spaces of gradient-like flows and Morse functions on surfaces are homotopy equivalent to manifolds.

Let SS be a set of critical points of a smooth real-valued function on a closed manifold MM. Generalizing a well-known result of Lusternik--Schnirelmann, Reeken~[R] proved that $\cat S \geq \cat M$. Here we prove a generalization of Reeken"s inequality for gradient-like flows on compact spaces.

1999-08-04abs ↗pdf ↗

We derive general Novikov-Morse type inequalities in a Conley type framework for flows carrying cocycles, therefore generalizing our results in [FJ2] derived for integral cocycle. The condition of carrying a cocycle expresses the nontriviality of integrals of that cocycle on flow lines. Gradient-like flows are distingu…

2003-11-30abs ↗pdf ↗

In this paper we develop a Morse theory for the uniform energy. We use the one-sided directional derivative of the distance function to study the minimizing properties of variations through closed geodesics. This derivative is then used to define a one-sided directional derivative for the uniform energy which allows us…

2016-09-29abs ↗pdf ↗

Given a complex analytic function f on a Whitney stratified complex analytic variety of complex dimension n, whose real part Re(f) is Morse, we prove the existence of a stratified gradient-like vector field for Re(f) such that the unstable set of a critical point p on a stratum S of complex dimension s has real dimensi…

2009-08-13abs ↗pdf ↗

In our previous paper math.DG/0010008, we develop some new techniques in attacking the convergence problems for the Kähler Ricci flow. The one of main ideas is to find a set of new functionals on curvature tensors such that the Ricci flow is the gradient like flow of these functionals. We successfully find such functio…

2001-08-27abs ↗pdf ↗

Study on stability of free boundary Willmore problem using new gradient inequality.

problem Stability of free boundary Willmore problem.
method New Łojasiewicz-Simon gradient inequality for functionals on infinite dimensional manifolds.
result Existence and convergence of solutions for the free boundary Willmore flow.

We develop the formal analogue of the Morse theory for a pair of commuting gradient-like vector fields. The resulting algebraic formalism turns out to be very similar to the algebra of the infrared of Gaiotto, Moore and Witten (see [GMW], [KKS]): from a manifold M with the pair of gradient-like commuting vector fields,…

2018-10-20abs ↗pdf ↗

This paper describes the construction of a canonical compactification of the space of trajectories and of the unstable/stable sets of a generic gradient like vector field on a closed manifold as well as a canonical structure of a smooth manifold with corners of these spaces. As an application we discuss the geometric c…

2011-01-04abs ↗pdf ↗

Let MM be a closed connected manifold, ff be a Morse map from MM to a circle, vv be a gradient-like vector field satisfying the transversality condition. The Novikov construction associates to these data a chain complex C=C(f,v)C_*=C_*(f,v). There is a chain homotopy equivalence between CC_* and completed simplicial cha…

2001-04-28abs ↗pdf ↗

We study the phase retrieval problem, which solves quadratic system of equations, i.e., recovers a vector xRn\boldsymbol{x}\in \mathbb{R}^n from its magnitude measurements yi=ai,x,i=1,...,my_i=|\langle \boldsymbol{a}_i, \boldsymbol{x}\rangle|, i=1,..., m. We develop a gradient-like algorithm (referred to as RWF representing reshaped W…

2016-05-25abs ↗pdf ↗

We will prove the equivariant version of Smale's transversality theorem: suppose that the compact Lie-group G acts on the compact differentiable manifold M on which an invariant Morse-function f and an invariant vector field X are given so that X is gradient-like with respect to f (i.e. X(f)<0 away from critical orbits…

2002-01-15abs ↗pdf ↗

Paper develops a gradient-like proposal for discrete distributions without requiring natural differentiability.

problem Lack of natural differentiability in proposal distributions for discrete distributions.
method Locally-balanced proposal combined with Newton's series expansion for efficient exploration.
result Method guarantees convergence rate and outperforms alternatives in various experiments.

We notice that a generic nonsingular gradient field v=fv = \nabla f on a compact 3-fold XX with boundary canonically generates a simple spine K(f,v)K(f, v) of XX. We study the transformations of K(f,v)K(f, v) that are induced by deformations of the data (f,v)(f, v). We link the Matveev complexity c(X)c(X) of XX with counting the …

2006-10-31abs ↗pdf ↗

Zeta invariants study Morse forms on Riemannian manifolds, proving smoothness and convergence.

problem Analyzing zeta invariants of Morse forms on Riemannian manifolds.
method Perturbations of de~Rham derivatives and Laplacians, heat semigroup, instantons, Mathai-Quillen currents.
result ζ(1,z) converges to a real number z as μ → ±∞ for Morse forms, describing preserved leaves in foliated flows.

The paper studies 3-manifolds with specific Morse-Smale diffeomorphisms and finds they are homeomorphic to lens spaces.

problem Understanding the topology of 3-manifolds with certain Morse-Smale diffeomorphisms.
method Analyzing the structure of fixed points and separatrices of diffeomorphisms in 3-manifolds.
result All supporting manifolds of these diffeomorphisms are homeomorphic to lens spaces.

Link concordance equals homotopy for high-dimensional spheres.

problem Understanding when immersions of high-dimensional spheres are homotopically trivial.
method Developed stratified Morse theory for generic immersions, using gradient-like vector fields and Cerf theory.
result Every link of high-dimensional spheres is homotopically trivial, resolving a long-standing conjecture.

Deep learning improves nearshore bathymetry estimation from sparse data.

problem Estimating nearshore bathymetry from limited and often sparse data.
method Deep Neural Network (DNN) and Conditional Generative Adversarial Network (cGAN) for posterior estimates; Kriging for comparison.
result DNN-based methods outperform traditional Kriging in predicting nearshore bathymetry with sharp gradients.

The paper examines Ricci flows with closed and smooth tangent flows, proving uniqueness and characterizing ancient flows.

problem Characterizing and understanding Ricci flows with closed and smooth tangent flows.
method Analyzing ancient and finite-time singularity Ricci flows to prove uniqueness and characterizations.
result The tangent flow is unique and characterizes ancient and finite-time singularity flows.

Study of twisted Calabi flow connecting J-flow and Calabi flow on Kähler manifolds.

problem Existence and convergence of twisted Calabi flow on compact Kähler manifolds.
method Analysis of a family of twisted Calabi flows connecting J-flow and Calabi flow, showing long-time existence and convergence to cscK metrics.
result Long-time existence and convergence of twisted Calabi flow to cscK metrics, implying openness of continuity method.

We consider four extended Ricci flow systems---that is, Ricci flow coupled with other geometric flows---and prove dynamical stability of certain classes of stationary solutions of these flows. The systems include Ricci flow coupled with harmonic map flow (studied abstractly and in the context of Ricci flow on warped pr…

2013-01-16abs ↗pdf ↗

The article calculates the F\mathbb{F}-convergence rate for Ricci flows with closed and smooth tangent flows.

problem Analyzing the convergence rate of Ricci flows with specific tangent flows.
method Calculating the F\mathbb{F}-convergence rate for Ricci flows with closed and smooth tangent flows.
result A Ricci flow with closed and smooth tangent flow is logλθ|\log λ|^{-θ} close to its tangent flow in the F\mathbb{F}-sense.

Study K-R flow on Hirzebruch surfaces, showing tangent flows are K-R flows with orbifold singularities.

problem Finite time singularities in Kähler-Ricci flow on Hirzebruch surfaces.
method Analyze tangent flows based at singular points.
result Tangent flows are K-R flows with orbifold singularities.

Ancient curve shortening flows have entropy and curvature bounds equivalent.

problem Bounding entropy and total curvature for ancient curve shortening flows.
method Equivalence of entropy and total curvature conditions for ancient curve shortening flows.
result Entropy and total curvature bounds are equivalent for ancient curve shortening flows.