In particular, if we assume that MT is modeled according to the log-linear model we can define softmax loss softmax (•) as follows: From Equation 21we can see that only the oracle translations contribute to the numerator, and all candidates in c (i) contributes to the denominator.
intuitively, the softmax objective prefers parameter settings that assign high scores to the oracle translations, and lower scores to any other members of c (i) that are not oracles.