@MISC{TOPS_1.MIZ,
  AUTHOR = {Wysocki, Miros{\l}aw and Darmochwa{\l}, Agata},
  TITLE = {Subsets of Topological Spaces},
  NOTE = {Supported by RPBP.III-24.C1.},
  DAY = {28},
  MONTH = {April},
  YEAR = {1989},
  ADDRESS1 = {Warsaw University\\Bia{\l}ystok},
  ADDRESS2 = {Warsaw University\\Bia{\l}ystok},
  SUMMARY = {The article contains some theorems about open and closed sets.
The following topological operations on sets are defined:
closure, interior and frontier.
The following notions are introduced: dense set,
boundary set, nowheredense set and set being domain (closed domain
and open domain), and some basic facts concerning them are proved.}}

