Curvature theory of generalized connection in .
Curvature-decreasing maps are volume-decreasing. On joint work with G. Besson and G. Courtois.
Curvatures and Curves in Hilbert Space.
Curvatures of conflict surfaces in Euclidean 3-space
This article extends to three dimensions results on the curvature of the conflict curve for pairs of convex sets of the plane, established by Siersma [3]. In the present case a conflict surface arises, equidistant from the given convex sets. The Gaussian, mean curvatures and the location of umbilic points on the conflict surface are determined here. Initial results on the Darbouxian type of umbilic points on conflict surfaces are also established. The results are expressed in terms of the principal...
Curvatures of the diagonal lift from an affine manifold to the linear frame bundle
We investigate the curvature of the so-called diagonal lift from an affine manifold to the linear frame bundle LM. This is an affine analogue (but not a direct generalization) of the Sasaki-Mok metric on LM investigated by L.A. Cordero and M. de León in 1986. The Sasaki-Mok metric is constructed over a Riemannian manifold as base manifold. We receive analogous and, surprisingly, even stronger results in our affine setting.
Curve shortening flow and the Banchoff-Pohl inequality on surfaces of nonpositive curvature.
Curve shortening makes convex curves circular.
Curve shortening on surfaces
Curved Casimir operators and the BGG machinery.
Curved flats in symmetric spaces.
Curved thin domains and parabolic equations
Consider the family uₜ = Δu + G(u), t > 0, , , t > 0, , of semilinear Neumann boundary value problems, where, for ε > 0 small, the set is a thin domain in , possibly with holes, which collapses, as ε → 0⁺, onto a (curved) k-dimensional submanifold of . If G is dissipative, then equation has a global attractor . We identify a “limit” equation for the family , prove convergence of trajectories and establish an upper semicontinuity result for the family as ε → 0⁺.
Curves and surfaces in hyperbolic space
In the first part (Sections 2 and 3), we give a survey of the recent results on application of singularity theory for curves and surfaces in hyperbolic space. After that we define the hyperbolic canal surface of a hyperbolic space curve and apply the results of the first part to get some geometric relations between the hyperbolic canal surface and the centre curve.
Curves in Banach spaces which allow a parametrization or a parametrization with finite convexity
We give a complete characterization of those (where is a Banach space) which allow an equivalent parametrization (i.e., a parametrization whose derivative has bounded variation) or a parametrization with bounded convexity. Our results are new also for . We present examples which show applicability of our characterizations. For example, we show that the and parametrization problems are equivalent for but are not equivalent for .
Curves in Lorentzian spaces
The notion of ``hyperbolic'' angle between any two time-like directions in the Lorentzian plane was properly defined and studied by Birman and Nomizu [1,2]. In this article, we define the notion of hyperbolic angle between any two non-null directions in and we define a measure on the set of these hyperbolic angles. As an application, we extend Scofield's work on the Euclidean curves of constant precession [9] to the Lorentzian setting, thus expliciting space-like curves in whose natural equations...
Curves in P² and symplectic packings.
Curves in the lightlike cone.
Curves of constant breadth
Curves of minimal order.
Curves with finite turn
In this paper we study the notions of finite turn of a curve and finite turn of tangents of a curve. We generalize the theory (previously developed by Alexandrov, Pogorelov, and Reshetnyak) of angular turn in Euclidean spaces to curves with values in arbitrary Banach spaces. In particular, we manage to prove the equality of angular turn and angular turn of tangents in Hilbert spaces. One of the implications was only proved in the finite dimensional context previously, and equivalence of finiteness...
Cusp closing in rank one symmetric spaces.