an fsg node. All transitions (words) out of any given FSG state represented are by a phonetic prefix lextree (except for epsilon or null transitions; they are not part of the lextree). Lextree leaf nodes represent individual FSG transitions, so no sharing is allowed at the leaf nodes. The FSG transition probs are distributed along the lextree: the prob at a node is the max of the probs of all leaf nodes (and, hence, FSG transitions) reachable from that node.
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an fsg node. All transitions (words) out of any given FSG state represented are by a phonetic prefix lextree (except for epsilon or null transitions; they are not part of the lextree). Lextree leaf nodes represent individual FSG transitions, so no sharing is allowed at the leaf nodes. The FSG transition probs are distributed along the lextree: the prob at a node is the max of the probs of all leaf nodes (and, hence, FSG transitions) reachable from that node.
To conserve memory, the underlying HMMs with state-level information are allocated only as needed. Root and leaf nodes must also account for all the possible phonetic contexts, with an independent HMM for each distinct context.