Reentrancy in feature structures

[John Beavers]

On Tue, 2 Jul 2002, Luis Casillas wrote:

> 4. A tree satisfies an atomic path equivalence PATH1 = PATH2 iff the
>    the subtree rooted at the node reached by following PATH1, and the
>    subtree rooted at the node reached by following PATH2, are identical.
>
> As far as I can see, reentrancy is just a way of guaranteeing that 4
> will hold.  Am I missing something?

Well, it seems to me that you've just replaced co-identification with some
notion of equivalence, and I don't think this makes a difference.  It
certainly wouldn't make any difference in whatever way you build such
models (even the problem of infinite recursion is still an issue if a path
is constrained to be equivalent to a superpath).  As far as the models
themselves, well, any dag you get as a model can be converted into a tree
algorithmically but you lose the equivalence information as part of the
data struture.  It seems to me that's the only difference, and depending
on whether you find that kind of information useful it could be an
unimportant difference.

My two cents,
John