[Ligncse256] POSTagger Trigrams

[Brent Payne]

We smoothed ours so that every possibility had some probability.  We still encounter -Infinity paths when decoding, so we might not have smoothed enough.

----- Original Message -----
From: "Andrea Biaggi" <abiaggi at cs.ucsd.edu>
To: ligncse256 at ling.ucsd.edu
Sent: Wednesday, February 18, 2009 12:16:11 AM GMT -08:00 US/Canada Pacific
Subject: [Ligncse256] POSTagger Trigrams

I have a question how to handle trigrams for P(t_i|t_{i-1}t_{i-2}).
It is always the case that this probability is >0 for every combinations 
of tags in the validation/test set using counts of the trigram in the 
training set?
Or we have to use a backoff/interpolation schema to handle all the 
possible cases? Or use some other techniques? Or just saying that it is 
= 0, therefore not a possible combination?

-- 
Andrea Biaggi abiaggi at cs.ucsd.edu

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