Generally, two edges can be re-combined if they satisfy the following two constraints: 1) the LHS (left-hand side) nonterminals are identical and the sub-alignments are the same (Zhang et al., 2006); and 2) the boundary words 1 on both sides of the partial translations are equal between the two edges (Chiang, 2007).
as shown in Figure 2, the decoder still generates 801 edges after the hypothesis re-combination.