696 search results - page 2 / 140 » A class of combinatorial identities |
COMBINATORICS
2002
13 years 6 months ago
2002
We investigate the numbers dk of all (isomorphism classes of) distributive lattices with k elements, or, equivalently, of (unlabeled) posets with k antichains. Closely related and...
JCT
2010
13 years 4 months ago
2010
Combinatorial proofs are given for certain entries in Ramanujan’s lost notebook. Bijections of Sylvester, Franklin, Wright, and Yee are employed. A new bijection, involving the n...
DM
2006
13 years 6 months ago
2006
By a very simple argument, we prove that if l, m, n {0, 1, 2, . . . } then l k=0 (-1)m-k l k m - k n 2k k - 2l + m = l k=0 l k 2k n n - l m + n - 3k - l . On the basis of this ide...
EJC
2008
13 years 6 months ago
2008
In this paper, the q
JCT
2007
13 years 5 months ago
2007
In answer to a question of Andrews about finding combinatorial proofs of two identities in Ramanujan’s “lost” notebook, we obtain weighted forms of Euler’s theorem on part...