Cubic Decomposition of 2-Orthogonal Polynomial Sequences

In the present work, we study the general cubic decomposition (CD) of a 2-orthogonal polynomial sequence, beginning with a characterization of all the elements involved in such CD. The recurrence coefficients of the 2-orthogonal sequences which admit a diagonal CD are described and we prove that the correspondent principal components are also 2-orthogonal. Finally, we analyse the CD of a 2-symmetric and 2-orthogonal sequence.