A sort generation SORT-GEN determines the same elements of signature and sentences as its list of SIG-DECLs, together with a corresponding sort generation constraint as a sentence of the underlying institution: all the sorts declared by the SIG-DECLs are generated by all the functions declared by the same. Note that this includes the embedding and projection functions associated with any declared subsort inclusions. A SORT-GEN is ill-formed if it does not declare any sorts.SORT-GEN ::= sort-gen SIG-DECL+