e the same as the green underlined
variable; Choose "different", an input box will appear to ask for a new
name if the red underlined variable is currently the same the green underlined
variable, and a "ne(red underlined variable, green underlined variable)"
will be added automatically; Choose "optional", an input box will appear
to allow user to type in a new name, but no "ne" clause will be added.</tt></li>

<li>
<tt>To remove a predicate from the edit window, click on the variable of
the predicate, then 