Formulas are constructed via
& (conjunction),
| (disjunction),
~ (negation) and parentheses. There are
no binding preferences between conjunction and disjunction, so they have to be
properly parenthesised. Atomic propositions
are any sequence of letters, e.g. a,
abc or
veryLongNameForMyAtomicProposition.
The literals T and
F are interpreted as truth and falsehood,
respectively.
An example formula is x & (c | d) & ~e.