Generalized Legendre-Stirling Numbers

K. C. Garrett¹, Kendra Killpatrick^2*

¹Department of Mathematics, Statistics and Computer Science, St. Olaf College, Northfield, MN, USA.
²Natural Science Division, Pepperdine University, Malibu, CA, USA.

DOI: 10.4236/ojdm.2014.44014                

Abstract

The Legendre-Stirling numbers were discovered by Everitt, Littlejohn and Wellman in 2002 in a study of the spectral theory of powers of the classical second-order Legendre differential operator. In 2008, Andrews and Littlejohn gave a combinatorial interpretation of these numbers in terms of set partitions. In 2012, Mongelli noticed that both the Jacobi-Stirling and the Legendre-Stirling numbers are in fact specializations of certain elementary and complete symmetric functions and used this observation to give a combinatorial interpretation for the generalized Legendre-Stirling numbers. In this paper we provide a second combinatorial interpretation for the generalized Legendre-Stirling numbers which more directly generalizes the definition of Andrews and Littlejohn and give a combinatorial bijection between our interpretation and the Mongelli interpretation. We then utilize our interpretation to prove a number of new identities for the generalized Legendre-Stirling numbers.

Keywords

Stirling Numbers, Legendre-Stirling Numbers, Set Partitions

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Mansour, T. (2012) Combinatorics of Set Partitions. Discrete Mathematics and Its Applications Series, Chapman and Hall/CRC an Imprint of Taylor and Francis LLC.
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[3]	Everitt, W.N., Littlejohn, L.L. and Wellman, R. (2002) Legendre Polynomials, Legendre-Stirling Numbers, and the Left-Definite Spectral Analysis of the Legendre Differential Expression. Journal of Computational and Applied Mathematics, 148, 213-238. http://dx.doi.org/10.1016/S0377-0427(02)00582-4
[4]	Andrews, G.E. and Littlejohn, L.L. (2009) A Combinatorial Interpretation of the Legendre-Stirling Numbers. Proceedings of the American Mathematical Society, 137, 2581-2590.
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