The Viterbi score, can be computed for all the states in the language model at t=t and then can advance to the time instant t=t+1, in an inductive manner, as formulated in 1.8 [, ]. This procedure is known as time synchronous Viterbi search because it completely processes at time t before going into the time t+1. Finally a backtracking pass gives the required state sequences. However even Viterbi search can be very expensive if the number of states is large. In such cases instead of keeping all candidates at every time frame t, only the first T candidates with the highest scores are allowed to retain. Others are discarded from further considerations. This procedure is known as beam search.