An Index Formula for Loewner Vector Fields
نویسندگان
چکیده
Let f be C2 real-valued function defined near 0 in R2, ∂2f ∂z2 6= 0 for z 6= 0. Motivated by the Carathéodory conjecture in differential geometry, Loewner conjectured that the index at 0 of the vector field given in complex notation by ∂ 2f ∂z2 is at most two. In this paper we establish a formula that computes the index of these Loewner vector fields from data about the hessian of f .
منابع مشابه
Morphology for Color Images via Loewner Order for Matrix Fields
Mathematical morphology is a very successful branch of image processing with a history of more than four decades. Its fundamental operations are dilation and erosion, which are based on the notion of a maximum and a minimum with respect to an order. Many operators constructed from dilation and erosion are available for grey value images, and recently useful analogs of these processes for matrix...
متن کاملA Poincaré-Hopf type formula for Chern character numbers
For two complex vector bundles admitting a homomorphism with isolated singularities between them, we establish a Poincaré-Hopf type formula for the difference of the Chern character numbers of these two vector bundles. As a consequence, we extend the original Poincaré-Hopf index formula to the case of complex vector fields.
متن کامل...with affection and respect, for all the pleasure of working with Xavier INDEX OF SINGULARITIES OF REAL VECTOR FIELDS ON SINGULAR HYPERSURFACES
Gómez-Mont, Seade and Verjovsky introduced an index, now called GSV-index, generalizing the Poincaré-Hopf index to complex vector fields tangent to singular hypersurfaces. The GSV-index extends to the real case. This is a survey paper on the joint research with Gómez-Mont and Giraldo about calculating the GSV-index IndV±,0(X) of a real vector field X tangent to a singular hypersurface V = f(0)....
متن کاملMorse’s index formula in VMO for compact manifolds with boundary
In this paper, we study Vanishing Mean Oscillation vector fields on a compact manifold with boundary. Inspired by the work of Brezis and Niremberg, we construct a topological invariant — the index — for such fields, and establish the analogue of Morse’s formula. As a consequence, we characterize the set of boundary data which can be extended to nowhere vanishing VMO vector fields. Finally, we s...
متن کاملGeneralized Degree and Optimal Loewner-type Inequalities
We generalize optimal inequalities of C. Loewner and M. Gromov, by proving lower bounds for the total volume in terms of the homotopy systole and the stable systole. Our main tool is the construction of an area-decreasing map to the Jacobi torus, streamlining and generalizing the construction of the first author in collaboration with D. Burago. It turns out that one can successfully combine thi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2006