| Even Signed Permutations Avoiding 2-Letter Signed Patterns |
| Received:December 27, 2007 Revised:February 28, 2008 |
| Key Words:
forbidden pattern signed permutation Catalan number.
|
| Fund Project:the National Natural Science Foundation of China (No.10801020). |
|
| Hits: 3067 |
| Download times: 2252 |
| Abstract: |
| Let ${\cal D}_n$ be the set of all signed permutations on $[n]=\{1,\dots, n\}$ with even signs, and let ${\cal D}_n(T)$ be the set of all signed permutations in ${\cal D}_n$ which avoids a set $T$ of signed patterns. In this paper, we find all the cardinalities of the sets ${\cal D}_n(T)$ where $T\subseteq B_2$. Some of the cardinalities encountered involve inverse binomial coefficients, binomial coefficients, Catalan numbers, and Fibonacci numbers. |
| Citation: |
| DOI:10.3770/j.issn:1000-341X.2009.05.006 |
| View Full Text View/Add Comment |
|
|
|
