To counter this effect, we reweight the branches by synchronizing the search process on word generation events.
each derivation (x i+1 , y i+1 ) ∈Ỹ(x i+1 ) that successfully generated the word x i+1 is reweighted by normalizing its importance weight: We subsequently reassign each derivation with a number of particles π (x i+1 , y i+1 ) proportional to its normalized weight.