[Cross-posted to developers and the delphinqa.]
After 16 years of teaching grammar engineering, I thought I’d found all of the ways in which one can be in the situation of seemingly being able to build an edge through interactive unification which isn’t in the chart. I’ve documented all of the ones I know about here:
Alas, I’ve found evidence of a new one. Or rather: I’m in that situation (together with a student) but none of the cases noted there apply. More specifically, with the grammar for Meithei [mni] that can be found here:
If we try to analyze this sentence:
yoŋ-siŋ túm-í čá-í
monkey-PL sleep-NHYP eat-NHYP
Monkeys sleep and eat.
The LKB and ace both return no parses found. If instead of using the two verbs (one intransitive and one transitive but with a dropped object), we repeat either one of the verbs, we get the expected parses (with both the LKB and ace).
yoŋ-siŋ čá-í čá-í
yoŋ-siŋ túm-í túm-í
Returning to the non-parsing sentence, and looking at the LKB’s parse chart, what’s missing is the VP-T built out of applying the VP1-TOP-COORD rule to the VP-B over čá-í and the VP over túm-í. Puzzlingly, I can build this edge interactively just fine. I’ve run out of guesses as to why it’s not showing up in the char and so I thought I’d put this puzzle out in case other DELPH-INites might be entertained by it.
p.s. Discourse directed me to an earlier discussion about this, where @johnca suggested checking that chart-packing-p is set to NIL. It is.