• π(h) is the probability of generating h ∈ [m] in the first position of a sequence.
• t(h |h) is the probability of generating h ∈ • o(x|h) is the probability of generating an A-HMM is an HMM in which each hidden state h is associated with at least one "anchor" observation state that can be generated by, and only by, h. Note that the anchor condition implies n ≥ m. An equivalent definition of an A-HMM is given by organizing the parameters in matrix form.