This work investigates on kernels that are applicable to semantic annotations expressed in Description Logics which are the
theoretical counterpart of the standard representations for the Semantic Web. Namely, the focus is on the definition of a
kernel for the
ALC\mathcal{ALC} logic, based both on the syntax and on the semantics of concept descriptions. The kernel is proved to be valid. Furthermore,
semantic distance measures are induced from the kernel function.