/// <summary>
/// Decompose this Sentence based on the rules of Truth Trees.
/// </summary>
/// <returns>The decomposition of this Sentence if it is decomposable, null otherwise.</returns>
public Decomposition decompose()
{
if (!isDecomposable())
{
return(null);
}
Decomposition ret = new Decomposition();
if (type == SentenceType.AND)
{
ret.left.Add(left);
ret.left.Add(right);
}
else if (type == SentenceType.OR)
{
ret.left.Add(left);
ret.right.Add(right);
}
else if (type == SentenceType.IF)
{
ret.left.Add(left.negation());
ret.right.Add(right);
}
else if (type == SentenceType.IFF)
{
ret.left.Add(left);
ret.left.Add(right);
ret.right.Add(left.negation());
ret.right.Add(left.negation());
}
else if (type == SentenceType.NOT)
{
if (left.type == SentenceType.AND)
{
ret.left.Add(left.left.negation());
ret.right.Add(left.right.negation());
}
else if (left.type == SentenceType.OR)
{
ret.left.Add(left.left.negation());
ret.left.Add(left.right.negation());
}
else if (left.type == SentenceType.IF)
{
ret.left.Add(left.left);
ret.left.Add(left.right.negation());
}
else if (left.type == SentenceType.IFF)
{
ret.left.Add(left.left);
ret.left.Add(left.right.negation());
ret.right.Add(left.left.negation());
ret.right.Add(left.right);
}
else if (left.type == SentenceType.NOT)
{
ret.left.Add(left.left);
}
}
return(ret);
}