@MISC{SUB_METR.MIZ,
  AUTHOR = {Lecko, Adam and Startek, Mariusz},
  TITLE = {Submetric Spaces --- Part {I}},
  NOTE = {Supported by RPBP.III-24.B3.},
  DAY = {27},
  MONTH = {September},
  YEAR = {1990},
  ADDRESS1 = {Technical Univercity of Rzesz\'ow},
  ADDRESS2 = {Technical University of Rzesz\'ow},
  NOTE2 = {,
  SUMMARY = {    Definitions of pseudometric space, nonsymmetric metric
 space, semimetric space and ultrametric space are introduced. We find some
 relations between these spaces and prove that every ultrametric space is
 a metric space. We define  the relation {\it is between}. Moreover
 we introduce the notions of the open segment and the closed segment.}}

