private bool ApplyGammaRules()
{
string rule = "Gamma rule";
HashSet <Node> nodes = new HashSet <Node>();
foreach (Node n in propositions)
{
if (n is UniversalQuantifier)
{
UniversalQuantifier quantifier = (UniversalQuantifier)n;
//add predicates for existing variables
foreach (char var in ActiveVariables)
{
try
{
UniversalQuantifier newQuantifier = (UniversalQuantifier)quantifier.Copy().ReplaceObjectVariableNewNode(quantifier.Variable, var);
if (quantifier != null)
{
nodes.Add(newQuantifier.Proposition);
}
}
catch (Exception ex) { DirectMessage.ShowError(ex.Message); }
}
}
else if (n is NegationSign && ((NegationSign)n).ReturnChildNode() is ExistentialQuantifier)
{
ExistentialQuantifier quantifier = (ExistentialQuantifier)((NegationSign)n).ReturnChildNode();
//add predicates for existing variables
foreach (char var in ActiveVariables)
{
try
{
ExistentialQuantifier newQuantifier = (ExistentialQuantifier)quantifier.Copy().ReplaceObjectVariableNewNode(quantifier.Variable, var);
if (quantifier != null)
{
nodes.Add(new NegationSign(newQuantifier.Proposition));
}
}
catch (Exception ex) { DirectMessage.ShowError(ex.Message); }
}
}
else
{
continue;
}
}
if (nodes.Count > 0 && !nodes.IsSubsetOf(propositions))
{
nodes.UnionWith(propositions);
leftNode = new STElement(nodes, ActiveVariables, rule);
SimplifyChild(leftNode);
return(true);
}
return(false);
}
private bool ApplyDeltaRules()
{
string rule = "Delta rule";
foreach (Node n in propositions)
{
if (n is ExistentialQuantifier)
{
HashSet <Node> props = new HashSet <Node>(propositions);
props.Remove(n);
//change variable
List <char> newVariables = AddNewVariable();
try
{
ExistentialQuantifier quantifier = (ExistentialQuantifier)n.Copy();
quantifier.ReplaceObjectVariable(quantifier.Variable, newVariables[newVariables.Count - 1]);
HashSet <Node> nodes = new HashSet <Node> {
quantifier.Proposition
};
props.UnionWith(nodes);
leftNode = new STElement(props, newVariables, rule);
SimplifyChild(leftNode);
return(true);
}
catch (Exception ex) { DirectMessage.ShowError(ex.Message); }
}
else if (n is NegationSign && ((NegationSign)n).ReturnChildNode() is UniversalQuantifier)
{
HashSet <Node> props = new HashSet <Node>(propositions);
props.Remove(n);
//change variable
List <char> newVariables = AddNewVariable();
try
{
UniversalQuantifier quantifier = (UniversalQuantifier)((NegationSign)n).ReturnChildNode().Copy();
quantifier.ReplaceObjectVariable(quantifier.Variable, newVariables[newVariables.Count - 1]);
HashSet <Node> nodes = new HashSet <Node> {
new NegationSign(quantifier.Proposition)
};
props.UnionWith(nodes);
leftNode = new STElement(props, newVariables, rule);
SimplifyChild(leftNode);
return(true);
}
catch (Exception ex) { DirectMessage.ShowError(ex.Message); }
}
else
{
continue;
}
}
return(false);
}