G. H. E. Duchamp, L. Poinsot, A. I. Solomon, K. A. Penson, P. Blasiak and A. Horzela, “Ladder Operators and Endomorphisms in Combinatorial Physics,” Discrete Mathematics and Theoretical Computer Science, Vol. 12, No. 2, 2010, pp. 23-46.

has been cited by the following article:

• TITLE: Generalized Powers of Substitution with Pre-Function Operators

  AUTHORS: Laurent Poinsot

  KEYWORDS: Formal Power Series; Formal Substitution; Riordan Group; Generalized Powers; Sheffer Sequences; Umbral Calculus

  JOURNAL NAME: Applied Mathematics, Vol.4 No.7A, July 5, 2013

  ABSTRACT: An operator on formal power series of the form S μS , where μ is an invertible power series, and σ is a series of the formt+（t2）is called a unipotent substitution with pre-function. Such operators, denoted by a pair (μ ，σ ） , form a group. The objective of this contribution is to show that it is possible to define a generalized powers for such operators, as for instance fractional powers σ for every .