Each cell in δ d 2 corresponds to a document d 1 ∈ D ( 1 ) , defined as: where {w } contains all the word types that appear in document d , and {w 1 } ∩ {w 2 } indicates all word pairs (w 1 , w 2 ) that can be found in a dictionary as translations.
(δ d 2 ) d 1 is the proportion of words in the document pair 2 ) that are translations of each other.