  Multi-valued logics have a long tradition in the literature on system
verification, including run-time verification. However, comparatively fewer
model-checking tools have been developed for multi-valued specification
languages. We present 3vLTL, a tool to generate Buchi automata from formulas in
Linear-time Temporal Logic (LTL) interpreted on a three-valued semantics. Given
an LTL formula, a set of atomic propositions as the alphabet for the automaton,
and a truth value, our procedure generates a Buchi automaton that accepts all
the words that assign the chosen truth value to the LTL formula. Given the
particular type of the output of the tool, it can also be seamlessly processed
by third-party libraries in a natural way. That is, the Buchi automaton can
then be used in the context of formal verification to check whether an LTL
formula is true, false, or undefined on a given model.
