[SCL] (abstract) vocabulary redux

[Robert E. Kent]

> this product. We make the requirement: the composition of this injective
map
> with the (two) product projections factor through F and the set seq(O) of
> sequences of O, respectively. This means that from comp(O) there are two
> surjective maps to F and to seq(O), respectively. Call these maps the
> function and sequence selectors. They are important for defining
> interpretations.

Actually, we only require the function selector to be surjective; that is,
that any term in F occurs in function position in some term in O. We do not
require that the O-sequence selector be surjective; that is, there may be
sequences of terms in O that do not appear in object position sequence.

BTW, note that the only constraint on R is that it be a subset of terms in
O.

Robert E. Kent
rekent at ontologos.org