We can re-write the first and last terms of Equation 9as: As in the previous section, we introduce an alignment variable, a, between t and p, giving: If we consider monotonic alignments, a defines again an alignment between a prefix of the system translation (t p ) and the user prefix, producing the suffix required in IMT (t s ) as the unaligned part.
we can re-write Pr(t | p, a) as: where Equation (16) has been obtained following a naïve Bayes' decomposition.