Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On linearly related orthogonal polynomials in several variables   Let $\{\mathbb{P}_n\}_{n\ge 0}$ and $\{\mathbb{Q}_n\}_{n\ge 0}$ be two monic
polynomial systems in several variables satisfying the linear structure
relation $$\mathbb{Q}_n = \mathbb{P}_n + M_n \mathbb{P}_{n-1}, \quad n\ge 1,$$
where $M_n$ are constant matrices of proper size and $\mathbb{Q}_0 =
\mathbb{P}_0$. The aim of our work is twofold. First, if both polynomial
systems are orthogonal, characterize when that linear structure relation exists
in terms of their moment functionals. Second, if one of the two polynomial
systems is orthogonal, study when the other one is also orthogonal. Finally,
some illustrative examples are presented.

21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex