public bool ExistentialQuantifierRule(ref DerivationStep s)
{
List <Node> temp = s.GetFormulas().ToList();
foreach (var n in s.GetFormulas())
{
int index = s.GetFormulas().IndexOf(n);
if (n is Existential e)
{
Existential newExist = FunctionHelper.DeepClone <Existential>(e);
temp.RemoveAt(index);
DerivationStep newStep = new DerivationStep(s.GetActiveVariables());
newStep.AddActiveVariable();
string checkVar = newExist.GetVariable().ToString();
this.ChangeVarHelperExist(newExist.RightNode, newStep.GetLastVar(), checkVar);
newStep.AddFormulas(newExist.RightNode);
newStep.Merge(temp);
s.RightNode = newStep;
this._branchingPoint.Push(s.RightNode);
return(true);
}
else if (n is Negation && n.RightNode is Universal u)
{
Universal newUni = FunctionHelper.DeepClone <Universal>(u);
temp.RemoveAt(index);
DerivationStep newStep = new DerivationStep(s.GetActiveVariables());
newStep.AddActiveVariable();
string checkVar = newUni.GetVariable().ToString();
this.ChangeVarHelperExist(newUni.RightNode, newStep.GetLastVar(), checkVar);
newStep.AddFormulas(new Negation("~", newUni.RightNode));
newStep.Merge(temp);
s.RightNode = newStep;
this._branchingPoint.Push(s.RightNode);
return(true);
}
}
return(false);
}
