Approximations to the MMI criterion and their effect on lattice-based MMI.
Table 3: WER on training data during 100 iterations of extended Baum-Welch using two different recognition methods.
['iteration', 'Method A', 'Method C']
Notice that the sequence of WERs are both slowing decreasing over this range. The only possible explanation for why these distributions are different is: by restricting the relevant sum in the definition of pθk(⋅∣x;κ,Vmle,Rk) to Vmle leads to ignoring transcriptions in W∖Vmle that have zero probability under θmle but non-trivial probability under θk.