Intermediate language

The intermediate language is based on the format provided by Mark Stckel's PTTP for formulas in negation normal form.

Here's its grammer:

$$\begin{array}{rcl} \langle\mbox{\sf formulas}\rangle&\to& \la... ...gle\vert\texttt{not\_}\langle\mbox{\sf atom}\rangle \end{array}$$

As an example for a syntactically correct knowledge base look at the aforementioned file adult.kb:

% facts
adult.

% default rules
adult :- student : adult.
not_employed :- student : not_employed.
not_married :- student : not_married.
employed:-adult:not_student.
married:-adult:not_student.

% initial query
query:-married;employed.