Here, f (m, d) is a feature function defined on modern word m paired with diplomatic word d, while w c is a weight vector corresponding to compositor c. To capture word-specific preferences we add an indicator feature for each pair of modern word m and diplomatic spelling d. We refer to these as WORD features below.
to capture general orthographic preferences we introduce an additional set of features based on the edit operations involved in the computation of Levenshtein distance between m and d. each operation is added as a separate feature, both with and without local context (previous or next character of the modern word).