private Clause resolve(Clause mainPremise, Clause sidePremise, int mainPremiseAtomIndex) {
// Rename the variables of the side premise
int numberOfVariablesMainPremise = mainPremise.getVariables().size();
Clause sidePremiseRenamed =
sidePremise.renameVariables(
this.m_saturator.getTermFactory(), numberOfVariablesMainPremise);
Term mainAtom = mainPremise.getBody()[mainPremiseAtomIndex];
Term sideAtom = sidePremiseRenamed.getHead();
Substitution unifier =
Substitution.mostGeneralUnifier(mainAtom, sideAtom, this.m_saturator.getTermFactory());
if (unifier == null) return null;
Set<Term> newBody = new LinkedHashSet<Term>();
// Copy the atoms from the main premise
for (int index = 0; index < mainPremise.getBody().length; index++) {
if (index != mainPremiseAtomIndex) {
Term newBodyAtom =
mainPremise.getBody()[index].apply(unifier, this.m_saturator.getTermFactory());
((FunctionalTerm) newBodyAtom).originIndex =
((FunctionalTerm) mainPremise.getBody()[index]).originIndex;
newBody.add(newBodyAtom);
}
}
// Copy the atoms from the side premise
for (int index = 0; index < sidePremiseRenamed.getBody().length; index++) {
Term newBodyAtom =
sidePremiseRenamed.getBody()[index].apply(unifier, this.m_saturator.getTermFactory());
((FunctionalTerm) newBodyAtom).originIndex = ((FunctionalTerm) mainAtom).originIndex;
newBody.add(newBodyAtom);
}
// New body and head
Term[] body = new Term[newBody.size()];
newBody.toArray(body);
Term head = mainPremise.getHead().apply(unifier, this.m_saturator.getTermFactory());
Clause resolvent = new Clause(body, head);
// Rename variables in resolvent
ArrayList<Variable> variablesResolvent = resolvent.getVariables();
HashMap<Variable, Integer> variableMapping = new HashMap<Variable, Integer>();
for (int i = 0; i < variablesResolvent.size(); i++) {
variableMapping.put(variablesResolvent.get(i), i);
}
Clause resolventRenamed =
resolvent.renameVariables(this.m_saturator.getTermFactory(), variableMapping);
return resolventRenamed;
}
