Urysohn's operators are a very important kind of nonlinear operators. Many scholars investigated their properties in various spaces. Similar to Urysohn's operators, a kind of nonlinear operators is introduced,...Urysohn's operators are a very important kind of nonlinear operators. Many scholars investigated their properties in various spaces. Similar to Urysohn's operators, a kind of nonlinear operators is introduced, and their continuity and complete continuity in a kind of Fenchel-Orlicz spaces are discussed in this paper. The results obtained are a generalization of the corresponding results in [1-4].展开更多
The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacel...The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacelike condition means that the tangent vector and the curvature vector span a spacelike 2-plane at each point of the curve γ under consideration. The assumption of index 1 is equivalent to saying that γ winds around some timelike axis with winding number 1. This reversed Fenchel-type inequality is proved by constructing a ruled spacelike surface with the given curve as boundary and applying the Gauss-Bonnet formula. As a by-product, this shows the existence of a maximal surface with γ as the boundary.展开更多
文摘Urysohn's operators are a very important kind of nonlinear operators. Many scholars investigated their properties in various spaces. Similar to Urysohn's operators, a kind of nonlinear operators is introduced, and their continuity and complete continuity in a kind of Fenchel-Orlicz spaces are discussed in this paper. The results obtained are a generalization of the corresponding results in [1-4].
基金supported by the National Natural Science Foundation of China(No.11471021)the Fundamental Research Funds for the Central Universities of China(No.531107050874)
文摘The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacelike condition means that the tangent vector and the curvature vector span a spacelike 2-plane at each point of the curve γ under consideration. The assumption of index 1 is equivalent to saying that γ winds around some timelike axis with winding number 1. This reversed Fenchel-type inequality is proved by constructing a ruled spacelike surface with the given curve as boundary and applying the Gauss-Bonnet formula. As a by-product, this shows the existence of a maximal surface with γ as the boundary.
