
<A NAME=FREEOF>

<TITLE>FREEOF</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>FREEOF</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
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The <em>freeof</em> logical operator returns 

<A HREF=r37_0122.html>true</A> if its first argument does 
not contain its second argument anywhere in its structure. 
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syntax: </H3>
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<em>freeof</em>(&lt;expression&gt;,&lt;kernel&gt;) or 
&lt;expression&gt; <em>freeof</em> &lt;kernel&gt; 
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&lt;expression&gt; can be any valid scalar REDUCE expression, &lt;kernel&gt; mus
t 
be a kernel expression (see <em>kernel</em>). 
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 <P> <H3> 
examples: </H3>
<P><PRE><TT>
a := x + sin(y)**2 + log sin z;
			 


                           2
  A := LOG(SIN(Z)) + SIN(Y)   + X 


if freeof(a,sin(y)) then write &quot;free&quot; else write &quot;not free&quot;;
			 


  not free 


if freeof(a,sin(x)) then write &quot;free&quot; else write &quot;not free&quot;;
			 


  free 


if a freeof sin z then write &quot;free&quot; else write &quot;not free&quot;;
			 


  not free

</TT></PRE><P>Logical operators can only be used in conditional expressions such
 as 
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<em>if</em>...<em>then</em> or <em>while</em>...<em>do</em>. 
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