  The Distributed Ontology Language (DOL) is currently being standardized
within the OntoIOp (Ontology Integration and Interoperability) activity of
ISO/TC 37/SC 3. It aims at providing a unified framework for (1) ontologies
formalized in heterogeneous logics, (2) modular ontologies, (3) links between
ontologies, and (4) annotation of ontologies.
  This paper focuses on an application of DOL's meta-theoretical features in
mathematical formalization: validating relationships between ontological
formalizations of mathematical concepts in COLORE (Common Logic Repository),
which provide the foundation for formalizing real-world notions such as spatial
and temporal relations.
