# Confusion in Understanding Viterbi Forward-Pass

I have a difficultly in understanding the Viterbi forward pass formula.

More Specifically what does “K” Represent and what is

From what I understand, shouldn’t be the same for all elements in a column. I understand it as the maximum probability from previous column.

Any Help is appreciated…

“max” in this formula is over the whole expression (not just c_{k,1} but combination of the three variables).

k is the row number of previous word (column).

It is explained in “Reading: Viterbi: Forward Pass”

So to populate a cell (i.e. 1,2) in the image above, you have to take the max of [kth cells in the previous column, times the corresponding transition probability of the kth POS to the first POS times the emission probability of the first POS and the current word you are looking at]

P.S. I agree that this notation is confusing, because in the picture, words are indexed from 1 to K and naturally k would mean the index of a column. But in this formula, k stands for 1 to N and I think notation should have been n in the formula. On the other hand in the week’s Assignment code, the column/word index in C is i

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Thank you @arvyzukai for the reply.

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