public static string NonRegularCheckWord(ArithmeticLanguage lang, int n, string word)
{
if (word.Length < n)
{
return("<false>Word is too short.</false>");
}
foreach (char c in word)
{
if (!lang.alphabet.Contains(c + ""))
{
return("<false>Word contains illegal letters.</false>");
}
}
if (lang.symbolic_string.isFlat())
{
SymbolicString wordSS = Parser.parseSymbolicString(word, lang.alphabet.ToList());
if (ProofChecker.checkContainment(wordSS, lang, LogicalExpression.True()))
{
return("<true></true>");
}
else
{
return("<false>Word is not in the language.</false>");
}
}
else
{
throw new PumpingLemmaException("Arithmetic Language must be flat!");
}
}
public static Tuple <string, string, string> NonRegularGetPumpableSplit(ArithmeticLanguage language, string word, int n)
{
foreach (var split in possibleSplits(word, n))
{
SymbolicString str = splitToSymbStr(language.alphabet.ToList(), split.Item1, split.Item2, split.Item3);
if (ProofChecker.checkContainment(str, language, LogicalExpression.True()))
{
return(split);
}
}
return(null);
}
public static bool NonRegularCheckI(ArithmeticLanguage language, string start, string mid, string end, int i)
{
string fullWord = pumpMid(start, mid, end, i);
if (language.symbolic_string.isFlat())
{
SymbolicString wordSS = Parser.parseSymbolicString(fullWord.ToString(), language.alphabet.ToList());
return(ProofChecker.checkContainment(wordSS, language, LogicalExpression.True()));
}
else
{
throw new PumpingLemmaException("Arithmetic Language must be flat!");
}
}
public static string NonRegularGetUnpumpableWord(ArithmeticLanguage language, SymbolicString unpumpableWord, int n)
{
Dictionary <VariableType, int> assignment = new Dictionary <VariableType, int>();
assignment.Add(VariableType.Variable("n"), n);
string word = pumpedWord(unpumpableWord, assignment);
SymbolicString ss = SymbolicString.FromTextDescription(language.alphabet.ToList(), word);
while (!ProofChecker.checkContainment(ss, language, LogicalExpression.True()))
{
assignment[VariableType.Variable("n")]++;
word = pumpedWord(unpumpableWord, assignment);
ss = SymbolicString.FromTextDescription(language.alphabet.ToList(), word);
}
return(word);
}
public static int NonRegularGetI(ArithmeticLanguage language, string start, string mid, string end)
{
SymbolicString matchingString = splitToSymbStr(language.alphabet.ToList(), start, mid, end);
if (ProofChecker.checkContainment(matchingString, language, LogicalExpression.True()))
{
return(1); // AI surrenders
}
else
{
int i = 0;
do
{
string word = pumpMid(start, mid, end, i);
SymbolicString ss = SymbolicString.FromTextDescription(language.alphabet.ToList(), word);
if (!ProofChecker.checkContainment(ss, language, LogicalExpression.True()))
{
return(i);
}
i++;
} while (i < 99); //for debugging purposes
return(-1);
}
}
