Footnotes

 

(1)

In fact Sig is a category, and Sen() and Mod() are functors. The categorial aspects of the semantics of CASL are emphasized in its formal semantics [Sem97c].

 

(2)

Implication may be taken as primitive, the other connectives being regarded as derived.

 

(3)

Definedness assertions may be derived from existential equations, or regarded as applications of fixed predicates.  

(4)

Strong equations may be derived from existential equations, using negation and disjunction; existential equations may be derived from strong equations and definedness assertions, or regarded as applications of fixed predicates.  

(5)

(The translation of such constraints along signature morphisms adds a further component, for technical reasons.)  

(6)

The present treatment of compound identifiers prevents full independence of the structuring constructs from the underlying institution, and it is being reconsidered.  

(7)

These restrictions are to be eliminated, by making explicit which parts of the parameter signatures may share with the body of the generic specification.