Reentrancy in feature structures

[John Beavers]

On Wed, 3 Jul 2002, Mike Maxwell wrote:

> it seems to me that the meaning of "identical" in Luis Casillas'
> definition is a crucial issue here.  Dredging something out of my old
> lisping days, I recall that Lisp made a distinction between (at least)
> two notions of "identical", often labeled "eq" and "equal".  One (I
> can't recall which) required identity of content (so e.g. two strings
> were equal under this definition if they were "spelled" the same), while
> the other required identity of reference (i.e. they were the same memory
> location).  I presume that condition 4 requires the latter (stronger)
> definition, correct?  In which case the equivalency really is just the
> same as re-entrancy, correct?

I'm not sure if that's what he meant, since that would be, as you said,
exactly the same as re-entrancy.

> Second (and assuming the answer to the first question is "yes"), I can
> think of one obvious case where this sort of thing makes a difference,
> namely with co-reference.  E.g. in some language where verbs are marked
> for agreement with subject and object, you would get a reflexive form
> only where the subject and object agreement features were identical in
> the strong sense.  (Otherwise you couldn't distinguish the translation
> equivalent of "He saw him" from "He saw himself.")

I'm not sure about this, either, or rather, it depends on how your binding
theory works.  Presumably you'd have to assume that indices that are
"equivalent" under the new definition are like those that are
token-identical as before and state your binding theory in these terms?
The agreement features don't need to be token identical provided you have
a story to say about the indices and what that means for equivalence of
agreement features, or at least that's how it seems to me.

Cheers,
John