Caloric polynomial

From HandWiki

In differential equations, the mth-degree caloric polynomial (or heat polynomial) is a "parabolically m-homogeneous" polynomial Pm(x, t) that satisfies the heat equation

∂P∂t=∂2P∂x2.

"Parabolically m-homogeneous" means

P(λx,λ2t)=λmP(x,t) for λ>0.

The polynomial is given by

Pm(x,t)=∑ℓ=0⌊m/2⌋m!ℓ!(m−2ℓ)!xm−2ℓtℓ.

It is unique up to a factor.

With t = −1, this polynomial reduces to the mth-degree Hermite polynomial in x.

References