Search Results - "Preston, Stephen C."
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Solar models and McKean’s breakdown theorem for the μCH and μDP equations
Published in Mathematische annalen (01-04-2023)“…We study the breakdown for μ CH and μ DP equations on the circle, given by m t + u m θ + λ u θ m = 0 , for m = μ ( u ) - u θ θ , where μ is the mean and λ = 2…”
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On the volumorphism group, the first conjugate point is always the hardest
Published in Communications in mathematical physics (01-10-2006)Get full text
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Isometric Immersions and the Waving of Flags
Published in Archive for rational mechanics and analysis (01-06-2024)“…In this article we propose a novel geometric model to study the motion of a physical flag. In our approach, a flag is viewed as an isometric immersion from the…”
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Vanishing Distance Phenomena and the Geometric Approach to SQG
Published in Archive for rational mechanics and analysis (01-03-2020)“…In this article we study the induced geodesic distance of fractional order Sobolev metrics on the groups of (volume preserving) diffeomorphisms and…”
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Geometric analysis of the generalized surface quasi-geostrophic equations
Published in Mathematische annalen (2024)“…We investigate the geometry of a family of equations in two dimensions which interpolate between the Euler equations of ideal hydrodynamics and the inviscid…”
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Shape Analysis of Surfaces Using General Elastic Metrics
Published in Journal of mathematical imaging and vision (01-10-2020)“…In this article, we introduce a family of elastic metrics on the space of parametrized surfaces in 3D space using a corresponding family of metrics on the…”
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Axisymmetric Diffeomorphisms and Ideal Fluids on Riemannian 3-Manifolds
Published in International mathematics research notices (01-01-2022)“…Abstract We study the Riemannian geometry of 3D axisymmetric ideal fluids. We prove that the $L^2$ exponential map on the group of volume-preserving…”
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Conjugate Points Along Kolmogorov Flows on the Torus
Published in Journal of mathematical fluid mechanics (01-05-2024)“…The geodesics in the group of volume-preserving diffeomorphisms (volumorphisms) of a manifold M , for a Riemannian metric defined by the kinetic energy, can be…”
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Geodesic completeness of the H3/2 metric on Diff(S1)
Published in Monatshefte für Mathematik (2020)“…Of concern is the study of the long-time existence of solutions to the Euler–Arnold equation of the right-invariant H 3 2 -metric on the diffeomorphism group…”
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Fredholm properties of Riemannian exponential maps on diffeomorphism groups
Published in Inventiones mathematicae (2010)“…We prove that exponential maps of right-invariant Sobolev H r metrics on a variety of diffeomorphism groups of compact manifolds are nonlinear Fredholm maps of…”
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The Geometry of Axisymmetric Ideal Fluid Flows with Swirl
Published in Arnold mathematical journal (01-06-2017)“…The sectional curvature of the volume preserving diffeomorphism group of a Riemannian manifold M can give information about the stability of inviscid,…”
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The geometry of whips
Published in Annals of global analysis and geometry (01-03-2012)“…In this article, we study geometric aspects of the space of arcs parameterized by unit speed in the L 2 metric. Physically, this corresponds to the motion of a…”
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A Geometric Rigidity Theorem for Hydrodynamical Blowup
Published in Communications in partial differential equations (08-10-2010)“…Suppose there is a smooth solution u of the Euler equation on a 3-dimensional manifold M, with Lagrangian flow η, such that for some Lagrangian path η(t, x)…”
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The WKB Method for Conjugate Points in the Volumorphism Group
Published in Indiana University mathematics journal (01-01-2008)“…Using the fact that ideal fluid flow corresponds to geodesics of a Riemannian metric on the volumorphism group, we show that the location of conjugate points…”
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Conjugate point criteria on the area-preserving diffeomorphism group
Published in Journal of geometry and physics (01-01-2023)“…This paper answers some questions about conjugate points along the geodesics corresponding to steady 2D Euler flows, posed by a paper of…”
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Liouville comparison theory for breakdown of Euler-Arnold equations
Published in Journal of Differential Equations (25-10-2024)“…In this article we study breakdown of solutions for (generalized) Euler-Arnold equations on Rn. Our method is based on treating the equation in Lagrangian…”
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Nonpositive curvature on the area-preserving diffeomorphism group
Published in Journal of geometry and physics (01-02-2005)“…A steady ideal fluid flow on a surface corresponds to a geodesic in the area-preserving diffeomorphism group. The sign of the curvature operator along this…”
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Geometric investigations of a vorticity model equation
Published in Journal of Differential Equations (05-01-2016)“…This article consists of a detailed geometric study of the one-dimensional vorticity model equationωt+uωx+2ωux=0,ω=Hux,t∈R,x∈S1, which is a particular case of…”
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The motion of whips and chains
Published in Journal of Differential Equations (01-08-2011)“…We study the motion of an inextensible string (a whip) fixed at one point in the absence of gravity, satisfying the equations η t t = ∂ s ( σ η s ) , σ s s − |…”
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Geodesic completeness of the $$H^{3/2}$$ metric on $$\mathrm {Diff}(S^{1})
Published in Monatshefte für Mathematik (01-10-2020)“…Of concern is the study of the long-time existence of solutions to the Euler--Arnold equation of the right-invariant $H^{3/2}$-metric on the diffeomorphism…”
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