click on the "Remove" button.</tt></li>

<li>
<tt>For this case , no extra editing require. so click "Add" button to
add new state to the state list on the right hand side of the window.</tt></li>

<li>
<tt>repeat previous procedure, to create another state which only contains
one predicate "outside_at(thing,place)" (see figure 4).</tt></li>

<li>
<tt>When all editing procedures are finished, click "Verify States" button
to verify states. If all states are valid then click "Commit" button to
add these state