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COMBINATORICS
2002
14 years 9 months ago
2002
Let A3(n, d, w) denote the maximum cardinality of a ternary code with length n, minimum distance d, and constant Hamming weight w. Methods for proving upper and lower bounds on A3...
COMBINATORICS
1998
14 years 9 months ago
1998
It is shown that there are 2n n − n−1 m=0 2n−m−1 2m m permutations which are the union of an increasing sequence and a decreasing sequence. 1991 Mathematics Subject Classi...
COMBINATORICS
1999
14 years 9 months ago
1999
We show how to count tilings of Aztec diamonds and hexagons with defects using determinants. In several cases these determinants can be evaluated in closed form. In particular, we...
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COMBINATORICS
1999
14 years 9 months ago
1999
We find, in the form of a continued fraction, the generating function for the number of (132)-avoiding permutations that have a given number of (123) patterns, and show how to ext...
COMBINATORICS
2004
14 years 9 months ago
2004
New conjectures are proposed on the numbers of FPL configurations pertaining to certain types of link patterns. Making use of the Razumov and Stroganov Ansatz, these conjectures a...