/**
  * Specifies that all variables in the proposition are either completely allowed (true) or
  * completely disallowed (false) for all of their categories.
  */
 public void setToTautology() {
   for (int i = 0; i < allowedCategories.length; i++) {
     setVariable(i, true);
   }
 }
 /** Sets the given value to true and all other values to false for the given variable. */
 public void setCategory(int variable, int category) {
   setVariable(variable, false);
   addCategory(variable, category);
 }