Doubt in CYK algorithm lecture

Doubt in CYK algorithm lecture

by Abhilaksh Kumar -
Number of replies: 2

Hi all

Can anyone please explain why this is a CFG? Here the set of non-terminals = {S} and set of pre-terminals is also = {S} (as in lexical rule, S -> a, 'S' appears on L.H.S.). However, shouldn't the set of preterminals (or PoS tags) be a "proper subset" of non-terminals by definition? In this case they are equal.

Thank you for your time and consideration

Regards

Abhilaksh  

In reply to Abhilaksh Kumar

Re: Doubt in CYK algorithm lecture

by Jean-Cédric Chappelier -
This is indeed a CFG. First of all, in CFG from a pure theoretical point of view there is no such thing a "preterminal", which is purely a practical NLP concept (corresponding to PoS tags, which have sense for NLP).
Secondly we never claimed that "preterminal" shall be a "proper subset"