Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Appell and Sheffer sequences: on their characterizations through
  functionals and examples   The aim of this paper is to present a new simple recurrence for Appell and
Sheffer sequences in terms of the linear functional that defines them, and to
explain how this is equivalent to several well-known characterizations
appearing in the literature. We also give several examples, including integral
representations of the inverse operators associated to Bernoulli and Euler
polynomials, and a new integral representation of the re-scaled Hermite
$d$-orthogonal polynomials generalizing the Weierstrass operator related to the
Hermite polynomials.

29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio