Recurrence relations with rational coefficients for multiple orthogonal polynomials determined by the Rodrigues formula (Q2446986)

The paper under review deals with multiple orthogonal polynomials, which are denominators of a sequence of Hermite-Padé approximants for a system of four functions. This paper is closely related with [\textit{D. V. Khristoforov}, Proc. Steklov Inst. Math. 272, S142--S151; translation from Sovrem. Probl. Mat. 9, 11--26 (2007; Zbl 1308.41014)]. The author obtains a set of recurrence relations with rational coefficients (with respect to the variables \(n\) and \(x\)) for the multiple orthogonal polynomials \(Q_{\vec{n}}\), involving multi-indexes of the form \(\vec{n}=(n,n,n,n)\) and \(\vec{n}=(n,n,n-1,n-1)\).