title: Prolog family relation how can i implement has child from one woman?
body: <p>In a data I have basic facts with <code>gender(_name,_gender)</code> and <code>parent(_parent,_child)</code>, 
  also I implement other rules.
  How can I implement this rule:</p>
  
  <pre><code>has_child_from_one_woman(_person):- 
  </code></pre>
  
  <p>I do something like this</p>
  
  <pre><code>has_child_from_one_woman(_person) :-
      parents(_mom,_person,_),
      not(parents(_other_mom,_person,__)),
      not(_mom \= _other_mom).
  </code></pre>
  
  <p>Is this true?
  The 3rd parameter of parents is an underscore</p>
  
  <pre><code>parents(_mother,_father,_child) :-
      mother(_mother,_child),
      father(_father,_child).
  </code></pre>