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    <h1>Unit 1</h1>
    <h2><u>Revision on Relation</u></h2>

<h3>1.1Revision on relation </h3>
    <p>
A <strong>Relation</strong> is a set of ordered pairs.
Given two sets A and B, a relation from A to B is defined as any subset of A x B.
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<p>
A relation on A is any subset of AX A.
Let R be a relation from A to B. Then,
<br>
<br>
Domain of R= {xe A: (x, y) = R, for some ye B}
<br>
<br>
Range of R = {ye B: (x, y) ER, for some xE A}
<br>
<br>
If R is a relation from A to B, then you may want to know what the inverse of R is.
The following definition explains what we mean by the inverse of a relation.
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<p class="def">
Definition 1.1
<br>
<br>
Let R be a relation from A to B. The inverse of R, denoted by R¹, is a relation from
B to A, given by<br><br>
R¹ = {(b, a): (a, b) &epsilon;R}.
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