## ABSTRACT

Just as it is reasonable to compute the odds of seeing a string pattern in a random sequence, so is the case with permutation patterns. We categorize permutation patterns as (1) unstructured and (2) structured. The former usually refers to the case where these patterns (or clusters) are

observed in sequences, usually defined on fairly large alphabet sets. The structured permutations refer to PQ trees, that is the encapsulation of

the common internal structure across all the occurrences of the permutation pattern. The question here is regarding the odds of seeing this structure (as a PQ tree) in a random sequence.