The purpose of this paper is to introduce and discuss the concept of topical functions on upward sets. We give characterizations of topical functions in terms of upward sets.
An excellent introduction to the topic of poset matroids is due to M, Barnabei, G, Nicoletti and L. Pezzoli. In this paper, we extensively study the closure operators of poset matroids and obtain the closure axioms fo...An excellent introduction to the topic of poset matroids is due to M, Barnabei, G, Nicoletti and L. Pezzoli. In this paper, we extensively study the closure operators of poset matroids and obtain the closure axioms for poset matroids; thereby we can characterize poset matroids in terms of the closure axioms. Some corresponding properties of combinatorial schemes are also obtained.展开更多
In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in t...In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in the set of optimal control variables.展开更多
The paper generalizes the classical Caristi＇s fixed point theorem. As an application. the classical Ekeland variational principle is generalized. In addition, it is proved that the generalized Caristi＇s fixed point ...The paper generalizes the classical Caristi＇s fixed point theorem. As an application. the classical Ekeland variational principle is generalized. In addition, it is proved that the generalized Caristi＇s fixed point theorem is equivalent to the generalized Ekeland variational principle.展开更多
文摘The purpose of this paper is to introduce and discuss the concept of topical functions on upward sets. We give characterizations of topical functions in terms of upward sets.
基金This research is supported partially by Education Ministry of China (No. 02139) by National Science Foundation of China(No. 10471038).
文摘An excellent introduction to the topic of poset matroids is due to M, Barnabei, G, Nicoletti and L. Pezzoli. In this paper, we extensively study the closure operators of poset matroids and obtain the closure axioms for poset matroids; thereby we can characterize poset matroids in terms of the closure axioms. Some corresponding properties of combinatorial schemes are also obtained.
文摘In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in the set of optimal control variables.
基金Tianyuan Young Mathematics of China under Grant (10526025)Science Foundation of Nanjing Normal University under Grant(2002SXXXGQ2B20)
文摘The paper generalizes the classical Caristi＇s fixed point theorem. As an application. the classical Ekeland variational principle is generalized. In addition, it is proved that the generalized Caristi＇s fixed point theorem is equivalent to the generalized Ekeland variational principle.
