منابع مشابه
Extended pattern avoidance
A 0-1 matrix is said to be extendably-avoiding if it can be the upper left corner of a-avoiding permutation matrix. This concept arose in EL], where the surprising result that the number of extendably 321-avoiding rectangles are enumerated by the ballot numbers was proved. Here we study the other ve patterns of length three. The main result is that the six patterns of length three divides into ...
متن کاملPattern avoidance in partial permutations ( extended abstract )
Motivated by the concept of partial words, we introduce an analogous concept of partial permutations. A partial permutation of length n with k holes is a sequence of symbols π = π1π2 · · ·πn in which each of the symbols from the set {1, 2, . . . , n− k} appears exactly once, while the remaining k symbols of π are “holes”. We introduce pattern-avoidance in partial permutations and prove that mos...
متن کاملPattern avoidance in alternating permutations and tableaux ( extended abstract )
We give bijective proofs of pattern-avoidance results for a class of permutations generalizing alternating permutations. The bijections employed include a modified form of the RSK insertion algorithm and recursive bijections based on generating trees. As special cases, we show that the sets A2n(1234) and A2n(2143) are in bijection with standard Young tableaux of shape 〈3〉. Alternating permutati...
متن کاملExtended Abstract for Enumerating Pattern Avoidance for Affine Permutations
In this paper we study pattern avoidance for affine permutations. In particular, we show that for a given pattern p, there are only finitely many affine permutations in S̃n that avoid p if and only if p avoids the pattern 321. We then count the number of affine permutations that avoid a given pattern p for each p in S3, as well as give some conjectures for the patterns in S4. This paper is just ...
متن کاملPattern Avoidance
Consider a sequence of letters or numbers. Does a pattern exist that is avoided by the sequence? This topic is a very popular area of research in mathematics for its promising utility in computer science and other branches of mathematics, the elegant proofs and solutions, and the many open problems that still remain. Section 1 of this paper provides definitions, notations, and some properties o...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2002
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(01)00259-x