Description logics (DLs) have recently been used to provide access to large amounts of data through a high-level conceptual interface, which is of relevance to both data integration and ontology-based data access. The fundamental inference service in this case is answering queries by taking into account the axioms in the TBox and the data stored in the ABox. The key property for such an approac...

We develop a formal framework for modular ontologies by analysing four notions ofconservative extension and their applications in refining, re-using, merging, and segment-ing ontologies. For two members of the DL-Lite family of description logics, we proveimportant meta-properties of these notions such as robustness under joins, vocabularyextensions, and iterated import of o...

In the title compound, C(4)H(9)N(2)O(3) (+)·NO(3) (-), alternatively called (1RS)-2-carbamoyl-1-carboxy-ethanaminium nitrate, the asymmetric unit comprises one asparaginium cation and one nitrate anion. The strongest cation-cation O-H⋯O hydrogen bond in the structure, together with other strong cation-cation N-H⋯O hydrogen bonds, generates a succession of infinite chains of R(2) (2)(8) rings al...