LaTeR: a general purpose manager of temporal information.

LaTeR is a manager of temporal information which can be used in a loosely-coupled way by different types of applications. LaTeR is based on a layered architecture: at the physical layer heterogeneous (qualitative and quantitative) temporal information is amalgamated using a constraint framework and temporal reasoning is performed; the interface layer provides a high-level language for manipulating and querying temporal information. The expressive power of the language has been defined in such a way that complete temporal reasoning is tractable. Particular attention has been devoted to the design of the query language and to efficient query processing. Since in LaTeR temporal reasoning is performed during data manipulation (insertion and/or deletion of information), the complexity of answering a query depends only on the length of the query and not on the dimension of the knowledge base.