摘要
Using ordered pairs,we can formulate themathematical theory of relations in set-theoreticlanguage.By a relation we mean here something likemarriage (between men and women) or belonging(between elements and sets).Looking at any specific relation,such asmarriage for instance,we might be tempted toconsider certain ordered pairs (x,y),namely justthose for which x is a man,y is a woman,and x ismarried to y.We have not yet seen the definition
Using ordered pairs, we can formulate the mathematical theory of relations in set-theoretic language. By a relation we mean here something like marriage （between men and women） or belonging （between elements and sets）.
