منابع مشابه
Simple Permutations Mix Well
We study the random composition of a small family of O(n3) simple permutations on {0, 1}n. Specifically we ask what is the number of compositions needed to achieve a permutation that is close to k-wise independent. We improve on a result of Gowers [1] and show that up to a polylogarithmic factor, n3k3 compositions of random permutations from this family suffice. We further show that the result ...
متن کاملSimple permutations mix even better
We study the random composition of a small family of O(n) simple permutations on {0, 1}n. Specifically we ask how many randomly selected simple permutations need be composed to yield a permutation that is close to k-wise independent. We improve on the results of Gowers [12] and Hoory et al. [13] and show that up to a polylogarithmic factor, nk compositions of random permutations from this famil...
متن کاملSimple permutations and pattern restricted permutations
A simple permutation is one that does not map any non-trivial interval onto an interval. It is shown that, if the number of simple permutations in a pattern restricted class of permutations is finite, the class has an algebraic generating function and is defined by a finite set of restrictions. Some partial results on classes with an infinite number of simple permutations are given. Examples of...
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This article studies the poset of simple permutations with respect to the pattern involvement. We specify results on critically indecomposable posets obtained by Schmerl and Trotter in [11] to simple permutations and prove that if σ, π are two simple permutations such that π < σ then there exists a chain of simple permutations σ (0) = σ, σ (1) ,. .. , σ (k) = π such that |σ (i) | − |σ (i+1) | =...
متن کاملSkew-merged Simple Permutations
The simple permutations in two permutation classes — the 321-avoiding permutations and the skew-merged permutations — are enumerated using a uniform method. In both cases, these enumerations were known implicitly, by working backwards from the enumeration of the class, but the simple permutations had not been enumerated explicitly. In particular, the enumeration of the simple skew-merged permut...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2005
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2005.09.016