Inversion-closed space has Daniell property
We construct in Bell-Kunen’s model: (a) a group maximal topology on a countable infinite Boolean group of weight and (b) a countable irresolvable dense subspace of . In this model .
We consider isometry groups of a fairly general class of non standard products of metric spaces. We present sufficient conditions under which the isometry group of a non standard product of metric spaces splits as a permutation group into direct or wreath product of isometry groups of some metric spaces.
The concepts of -systems, -networks and -covers were defined by A. Arhangel’skiǐ in 1964, P. O’Meara in 1971 and R. McCoy, I. Ntantu in 1985, respectively. In this paper the relationships among -systems, -networks and -covers are further discussed and are established by -systems. As applications, some new characterizations of quotients or closed images of locally compact metric spaces are given by means of -systems.
In this paper we establish Kannan-type cyclic contraction results in probabilistic 2-metric spaces. We use two different types of -norm in our theorems. In our first theorem we use a Hadzic-type -norm. We use the minimum -norm in our second theorem. We prove our second theorem by different arguments than the first theorem. A control function is used in our second theorem. These results generalize some existing results in probabilistic 2-metric spaces. Our results are illustrated with an example....