[CL] CLIF terms and atoms

[Randall R Schulz]

On Monday November 23 2009, Cameron Ross wrote:
> ... 
> Is a fragment of CLIF text such as "(a b)" a term or an atom?

Absolutely.

CLIFs grammar does not allow free-standing terms, so if "(a b)" is the 
totality of the input, then it is a formula, an atomic formula, that 
applies the predicate "a" to the individual constant "b." Furthermore, 
while complex terms (those that apply functions) may nest arbitrarily, 
the same is not true for atomic formulas (predicate application), which 
do not nest at all.

Thus the ambiguity is resolved.

However, if you "zoom in" on some CLIF and see the substring "(a b)" and 
cannot see the context in which it appears, you cannot say whether 
you're looking at an atomic (sub-) formula or a (sub-) term.

By the way, this: "(a (a b))" is also legal CLIF, but "a" is used both 
as a unary predicate and as a unary function therein.


> Cameron.


Randall Schulz