@MISC{TOLER_1.MIZ,
  AUTHOR = {Hryniewiecki, Krzysztof},
  TITLE = {Relations of Tolerance},
  NOTE = {Supported by Philippe le Hodey Foundation. This work had been done on Mizar
Workshop '89 (Foudrain, France) in Summer '89.},
  DAY = {20},
  MONTH = {September},
  YEAR = {1990},
  ADDRESS1 = {Warsaw University},
  SUMMARY = {  Introduces notions of relations of tolerance,
tolerance set and neighbourhood of an element.
The basic properties of relations of tolerance are proved.}}

