In order to obtain a semantic foundation for heterogeneous specification, we extend Diaconescu's morphism-based Grothendieck institutions to the case of comorphisms. This is not just a dualization, because we obtain more general results, especially concerning amalgamation properties. We also introduce a proof calculus for structured heterogeneous specifications and study its soundness and completeness (where amalgamation properties play a role for obtaining the latter).
['Till Mossakowski']
Comorphism-based Grothendieck logics