x n−1..n with a left context χ → , we define its Right Branching Entropy (RBE) as: The Left Branching Entropy (LBE) is defined in a symmetric way: if we note χ ← the right context of x 0..n , its LBE is defined as: The RBE (resp.
we improve on (Jin and Tanaka-Ishii, 2006) by adding normalization and viterbidecoding.