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.
In this work, we are interested in the differential geometry of surfaces in simply isotropic I3 and pseudo-isotropic Ip3 spaces, which consists of the study of R3 equipped with a degenerate metric such as ds2=dx2±dy2. The investigation is…
We give a positive answer to the Chavel's conjecture [J. Diff. Geom. 4 (1970), 13-20]: a simply connected rank one normal homogeneous space is symmetric if any pair of conjugate points are isotropic. It implies that all simply connected rank one normal homogeneous space with the property that the isotropy action is var…
It was shown by Ramanathan \cite{R} that any compact oriented non-simply-connected minimal surface in the three-dimensional round sphere admits at most a finite set of pairwise noncongruent minimal isometric immersions. Here we show that this result extends to isotropic surfaces in spheres of arbitrary dimension. The c…
In this work, we are interested in the differential geometry of curves in the simply isotropic and pseudo-isotropic 3-spaces, which are examples of Cayley-Klein geometries whose absolute figure is given by a plane at infinity and a degenerate quadric. Motivated by the success of rotation minimizing (RM) frames in Eucli…
In this paper we study the topology of compact manifolds of positive isotropic curvature (PIC). There are many examples of non-simply connected compact manifolds with positive isotropic curvature. We prove that the fundamental group of a compact Riemannian manifold with PIC, of dimension greater than or equal to 5, doe…
We study the Jacobi osculating rank of geodesics on naturally reductive homogeneous manifolds and we apply this theory to the 3-dimensional case. Here, each non-symmetric, simply connected naturally reductive 3-manifold can be given as a principal bundle over a surface of constant curvature, such that the curvature of …
Let (Mn,g), n≥4, be a compact simply-connected Riemannian manifold with nonnegative isotropic curvature. Given 0<l≤L, we prove that there exists $\eps = \eps (l,L,n)$ satisfying the following: If the scalar curvature s of g satisfies l≤s≤L and the Einstein tensor satisfies $$ | Ric - \fr…
Let M be a complete Riemannian manifold and suppose p∈M. For each unit vector v∈TpM, the Jacobi operator, Jv:v⊥→v⊥ is the symmetric endomorphism, Jv(w)=R(w,v)v. Then p is an isotropic point if there exists a constant $κ_p \in \mat…
The study of Bonnet surfaces in 4D space forms reveals new conformally invariant properties and characterizes proper Bonnet surfaces.
problem Investigating Bonnet surfaces in 4D space forms with constant mean curvature.
method Analyzing the moduli space of congruence classes of isometric surfaces, studying properties of lines of curvature, and using infinitesimal isometric deformations.
result Isotropic isothermicity characterizes proper Bonnet surfaces and provides conditions for non-existence of Bonnet mates.
In this paper, we show the existence of real-analytic stationary Navier-Stokes flows with isotropic streamlines in all latitudes in some simply-connected flow region on a rotating round sphere. We also exclude the possibility of having a Poiseuille's flow profile to be one of these stationary Navier-Stokes flows with i…
A central theme in Riemannian geometry is understanding the relationships between the curvature and the topology of a Riemannian manifold. Positive isotropic curvature (PIC) is a natural and much studied curvature condition which includes manifolds with pointwisequarter-pinched sectional curvatures and manifolds with p…
The existence of a recurrent spinor field on a pseudo-Riemannian spin manifold (M,g) is closely related to the existence of a parallel 1-dimensional complex subbundle of the spinor bundle of (M,g). We characterize the following simply connected pseudo-Riemannian manifolds admitting such subbundles in terms of their…
We study equivariant contact structures on complex projective varieties arising as partial flag varieties G/P, where G is a connected, simply-connected complex simple group of type ADE and P is a parabolic subgroup. We prove a special case of the LeBrun-Salamon conjecture for partial flag varieties of these typ…
Let L\subset V=\bR^{k,l} be a maximally isotropic subspace. It is shown that any simply connected Lie group with a bi-invariant flat pseudo-Riemannian metric of signature (k,l) is 2-step nilpotent and is defined by an element η\in Λ^3L\subset Λ^3V. If ηis of type (3,0)+(0,3) with respect to a skew-symmetric endomorphis…
In this paper, we find a condition on (α,β)-metrics under which the notions of isotropic S-curvature, weakly isotropic S-curvature and isotropic mean Berwald curvature are equivalent.
We study two types of isotropic planes: weakly isotropic and strongly isotropic planes. We prove that a Riemannian manifold of indefinite metric is conformally flat if and only if its curvature tensor vanishes on all the strongly isotropic planes. We specialize the plane axiom for Riemannian manifolds of indefinite met…
In this paper, we construct a new class of Finsler manifolds called generalized isotropic Berwald manifolds which is an extension of the class of isotropic Berwald manifolds. We prove that every generalized isotropic Berwald manifold is a generalized Douglas-Weyl manifold. On a compact generalized isotropic Berwald man…
In this paper we will show that a Lagrangian, Lorentzian surface M12 in a complex pseudo space form M12(4c) is pseudo-isotropic if and only if M is minimal. Next we will obtain a complete classification of all Lagrangian, Lorentzian surfaces which are lightlike pseudo-isotropic but not pseudo-isot…
We show that for m>n≥2, there are at least two exact isotropic n-tori in Cm which are not Hamiltonian isotopic in Cm, even though they are smoothly isotopic as isotropic n-tori. We apply this discovery to obtain more distinct non-exact isotropic tori in Cm.
This paper aims to provide a description of totally isotropic Willmore two-spheres and their adjoint transforms. We first recall the isotropic harmonic maps which are introduced by Hélein, Xia-Shen and Ma for the study of Willmore surfaces. Then we derive a description of the normalized potential (some Lie algebra valu…