  Requirements engineering is a key phase in the development process. Ensuring
that requirements are consistent is essential so that they do not conflict and
admit implementations. We consider the formal verification of rt-consistency,
which imposes that the inevitability of definitive errors of a requirement
should be anticipated, and that of partial consistency, which was recently
introduced as a more effective check. We generalize and formalize both notions
for discrete-time timed automata, develop three incremental algorithms, and
present experimental results.
