A Metric Index for Approximate String Matching

Abstract. We present a radically new indexing approach for approxi-mate string matching. The scheme uses the metric properties of the edit distance and can be applied to any other metric between strings. We build a metric space where the sites are the nodes of the sux tree of the text, and the approximate query is seen as a proximity query on that metric space. This permits us nding the R occurrences of a pattern of length m in a text of length n in average time O(m log 2 n+m 2 +R), using O(n log n) space and O(n log 2 n) index construction time. This complex-ity improves by far over all other previous methods. We also show