feature structures vs. feature structure descriptions

[Ivan A. Sag]

Dear Lutz,

I just wanted to add one point relevant to this discussion. You cited a
passage from a version of Sag and Wasow that has undergone considerable
revision. The published version of the textbook makes clear that the general
principles of the grammar are constraints on feature structures (or rather
phrase structures, until Chapter 16). I believe there is no significant
discrepancy between the grammar of the textbook and the theoretical approach
that Carl describes, though our pedagogical approach is to build up to HPSG
step by step from CFG, keeping trees in the picture as long as possible.  I
hope the book will be available at the end of this month...


All best,
Ivan