We introduce multivariable generalized forms of Hermite polynomials an
d analyze both the Gould-Hopper type polynomials and more general form
s, which are analogues of the classical orthogonal polynomials, since
they represent a basis ill L2(R(N)) Hilbert space, suitable for series
expansion of square summable functions of N variables: Moreover, the
role played by these generalized Hermite polynomials in the solution o
f evolution-type differential equations is investigated: The key-note
of the method leading to the multivariable polynomials is the introduc
tion of particular generating functions, following the same criteria u
nderlying the theory of multivariable generalized Bessel functions.