tailieunhanh - Báo cáo toán học: "Wilf-equivalence on k-ary words, compositions, and parking functions"

Tuyển tập các báo cáo nghiên cứu khoa học về toán học trên tạp chí toán học quốc tế đề tài: Wilf-equivalence on k-ary words, compositions, and parking functions. | Wilf-equivalence on k-ary words compositions and parking functions Vit Jelinek Department of Applied Mathematics Charles University Prague jelinek@ Toufik Mansour Department of Mathematics Haifa University 31905 Haifa Israel toufik@ Submitted May 9 2008 Accepted May 4 2009 Published May 11 2009 Mathematics Subject Classification Primary 05A18 Secondary 05E10 05A17 05A19 Abstract In this paper we study pattern-avoidance in the set of words over the alphabet k . We say that a word w E k n contains a pattern T E k m if w contains a subsequence order-isomorphic to T. This notion generalizes pattern-avoidance in permutations. We determine all the Wilf-equivalence classes of word patterns of length at most six. We also consider analogous problems within the set of integer compositions and the set of parking functions which may both be regarded as special types of words and which contain all permutations. In both these restricted settings we determine the equivalence classes of all patterns of length at most five. As it turns out the full classification of these short patterns can be obtained with only a few general bijective arguments which are applicable to patterns of arbitrary size. 1 Introduction In this paper we study patterns avoidance in the domains of words integer partitions and parking functions. This can be seen as an extension of the frequently studied concept of pattern avoidance of permutation patterns. Our results extend previous work of Burstein 4 who described the equivalence classes of k-ary words of length at most 3 and Supported by the project MSM0021620838 of the Czech Ministry of Education and by the grant GD201 05 H014 of the Czech Science Foundation. THE ELECTRONIC JOURNAL OF COMBINATORICS 16 2009 R58 1 of Savage and Wilf 14 who described the equivalence classes of integer compositions of length at most 3. Our classification is largely based on several new bijective arguments inspired by the ideas from Krattenthaler

TÀI LIỆU LIÊN QUAN
TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.