Question 964861
<pre>
We cannot tell what "(X  Y)  W" means.

It could be any of these 4.  

(X &#8898; Y) &#8898; W
(X &#8898; Y) &#8899; W
(X &#8899; Y) &#8898; W
(X &#8899; Y) &#8899; W

You can tell me in the answer note form below, and I'll get
back to you by email.  You can use the letter capital U for 
union, &#8899;, and the little letter n for intersection, &#8898;, like 
this:

(X n Y) n W
(X n Y) U W
(X U Y) n W
(X U Y) U W

Edwin</pre>