Theresa L. Friedman, Paul Klingsberg, "Combinatorial identities by way of Wilf's multigraph model", International Journal of Mathematics and Mathematical Sciences, vol. 2006, Article ID 096327, 10 pages, 2006. https://doi.org/10.1155/IJMMS/2006/96327
Combinatorial identities by way of Wilf's multigraph model
For many families of combinatorial objects, a construction of Wilf (1977) allows the members of the family to be viewed as paths in a directed multigraph. Introducing a partition of these paths generates a number of known, but hitherto disparate, combinatorial identities. We include several examples.
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