# Geometry of Two-Variable Laguerre Polynomials

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On the left is a three-dimensional plot of a Laguerre polynomial in two variables and ; on the right is a two-dimensional plot of the surface cut by a plane perpendicular to the axis. The exponential operator transform is defined in the Details.

Contributed by: Marcello Artioli and Giuseppe Dattoli (June 2015)

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

The two-variable Laguerre polynomials

have been shown to be solutions of the following partial differential equation:

.

The operator

is called the Laguerre derivative since

,

and it exhibits the following notable property:

.

Therefore, it is easily shown that the solution of the above equations, written in an operational form, reads:

.

The preceding formulas suggest geometrical representations for the two-variable Laguerre polynomials, which are displayed in the graphics. The exponential operator transforms an ordinary monomial into a polynomial of the Laguerre type. The monomial-to-polynomial transition is shown by moving the cutting plane orthogonal to the axis. For a specific value of the polynomial degree , the polynomials lie on the cutting plane.

References

[1] P. Appell and J. K. de Fériet, *Fonctions hypergéométriques et hypersphériques: polynômes d'Hermite*, Paris: Gauthier-Villars, 1926.

[2] G. Dattoli, "Generalized Polynomials, Operational Identities and Their Applications," *Journal of Computational and Applied Mathematics*, 118(1–2), 2000 pp. 111–123. doi:10.1016/S0377-0427(00)00283-1.

## Permanent Citation