On multivariate orthogonal polynomials and elementary symmetric functions

AbstractWe study families of multivariate orthogonal polynomials with respect to the symmetric weight function indvariables$$\begin{aligned} B_{\gamma }(\mathtt {x}) = \prod \limits _{i=1}^{d} \omega (x_{i}) \prod \limits _{i<j} |x_{i}-x_{j}|^{2\gamma +1}, \quad \mathtt {x}\in (a,b)^{d}, \end{aligned}$$Bγ(x)=∏i=1dω(xi)∏i<j|xi-xj|2γ+1,x∈(a,b)d,for$$\gamma >-1$$γ>-1, where$$\omega (t)$$ω(t)is an univariate weight function in$$t \in (a,b)$$t∈(a,b)and$$\mathtt {x} = (x_{1},x_{2}, \ldots , x_{d})$$x=(x1,x2,…,xd)with$$x_{i} \in (a,b)$$xi∈(a,b). Applying the change of variables$$x_{i},$$xi,$$i=1,2,\ldots ,d,$$i=1,2,…,d,into$$u_{r},$$ur,$$r=1,2,\ldots ,d$$r=1,2,…,d, where$$u_{r}$$uris ther-th elementary symmetric function, we obtain the domain region in terms of the discriminant of the polynomials having$$x_{i},$$xi,$$i=1,2,\ldots ,d,$$i=1,2,…,d,as its zeros and in terms of the corresponding Sturm sequence. Choosing the univariate weight function as the Hermite, Laguerre, and Jacobi weight functions, we obtain the representation in terms of the variables$$u_{r}$$urfor the partial differential operators such that the respective Hermite, Laguerre, and Jacobi generalized multivariate orthogonal polynomials are the eigenfunctions. Finally, we present explicitly the partial differential operators for Hermite, Laguerre, and Jacobi generalized polynomials, for$$d=2$$d=2and$$d=3$$d=3variables.