The characterizations of upper approximation operators based on special coverings

• Autorzy: Pei Wang , Qingguo Li
• Języki publikacji: EN

Abstrakty

EN

In this paper, we discuss the approximation operators [...] apr¯NS ${\overline {apr} _{NS}}$ and [...] apr¯S ${\overline {apr} _S}$ which are based on NS(U) and S. We not only obtain some properties of NS(U) and S, but also give examples to show some special properties. We also study sufficient and necessary conditions when they become closure operators. In addition, we give general and topological characterizations of the covering for two types of covering-based upper approximation operators being closure operators.

Słowa kluczowe

EN

Upper approximation operator; Closure operator; Base; Topology

Kategorie tematyczne

• 54-00: General reference works (handbooks, dictionaries, bibliographies, etc.)
• 54A99: None of the above, but in this section
• 54A10: Several topologies on one set (change of topology, comparison of topologies, lattices of topologies)

• Wydawca: De Gruyter Open
• Czasopismo: Open Mathematics
• Rocznik: 2017
• Tom: 15
• Numer: 1
• Strony: 193-202

Daty

wydano

2017-01-01

otrzymano

2016-07-23

zaakceptowano

2017-01-17

online

2017-03-04

Twórcy

autor

Pei Wang

• College of Mathematics and Econometrics, Hunan University, Hunan, 410012, China and School of Mathematics and Information Science, Guangxi Universities Key Lab of Complex System Optimization and Big Data Processing, Yulin Normal University, Yulin 537000,

autor

Qingguo Li

• College of Mathematics and Econometrics, Hunan University, Hunan, 410012,

Identyfikatory

DOI

10.1515/math-2017-0015