Algorithmic Combinatorics Seminar, Winter 1994/95

Time: every Friday, 1030 - 1200

Place: Seminarraum Schloß Hagenberg

14.10. Peter Paule Organisational items
21.10. Roberto Pirastu On the algebraic-combinatorial structure of Umbral Calculus (work with G. Nicoletti/Bologna)

Abstract: In this and in the following talks we present a combinatorial point of view for a general umbral calculus only based on the structure of vector space and coalgebra.

28.10. Roberto Pirastu Umbral Calculus (part II)
4.11. Roberto Pirastu Umbral Calculus (part III)
18.11. Istvan Nemes Multisecting degenerate recurrences
2.12. Axel Riese On automated proofs of q-identities
9.12. canceled
16.12. Ziming Li A note on the computation of cyclotomic factors of a resultant.

Abstract: In this talk we propose a method for obtaining cyclotomic factors of a resultant without computing the resultant explicitly. By the method we may get rid of intermediate expression as well.

Istvan Nemes Invertible elements in Hadamard Algebras

Abstract: Continuing my previous talk on multisection of sequences I show how to decide in the Hadamard algebra of C- and P-recursive sequences that a sequence is invertible. As an application I propose a simpler mean for finding m-hypergeometric solutions of recurrence relations than was given by Petkovsek and Salvy.

13.01. Peter Paule Survey/Introduction to q-identities
20.01. canceled
27.01. Christian Mallinger Holonomic functions in Koepf' s approach

Abstract: I will continue the talk which started in November 1994. Wolfram Koepf gave an approach for Computing the Power Series expansion of certain classes of functions. In my talk I will (try to) close some gaps that Koepf left. I will specify some parts of his algorithm for holonomic functions. Moreover, I will state some question that arose when I was working with this subject.