t>may cause</tt> <i>F</i> <tt>if</tt> <i>G</i>
</center>

<p>is expanded into<p>

<center>
<tt>caused</tt> <i>F</i> <tt>if</tt> <i>F</i>
                         <tt>after</tt> <i>A</i> <tt>&</tt> <i>G.</i>
</center>

<p>-- if <i>F</i> holds after the execution of action <i>A</i> in a state
satisfying condition <i>G</i> then there is a cause for this.  In other
words, <i>F</i> is a possible outcome of <i>A</i>; <i>F</i> is allowed to
become true after executing <i>A</i>, but this outcome is not required.<p>