@MISC{RELAT_1.MIZ,
  AUTHOR = {Woronowicz, Edmund},
  TITLE = {Relations and Their Basic Properties},
  DAY = {15},
  MONTH = {March},
  YEAR = {1989},
  ADDRESS1 = {Warsaw University\\Bia{\l}ystok},
  SUMMARY = {   We define here: mode Relation as a set of pairs, the domain,
the codomain, and the field of relation;
the empty and the identity relations, the composition of relations,
the image and the inverse image of a set under a relation.
Two predicates, = and $\subseteq$, and three functions,
 $\cup$, $\cap$ and $\setminus$ are redefined.
Basic facts about the above mentioned notions are presented.}}

