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arXiv · 2210.02566

On Sums, Derivatives, and Flips of Riordan Arrays

Caroline Bang·Matias von Bell·Eric Culver·Jessica Dickson·Stoyan Dimitrov·Rachel Perrier·Sheila Sundaram
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Abstract

We study three operations on Riordan arrays. First, we investigate when the sum of Riordan arrays yields another Riordan array. We characterize the $A$- and $Z$-sequences of these sums of Riordan arrays, and also identify an analog for $A$-sequences when the sum of Riordan arrays does not yield a Riordan array. In addition, we define the new operations `Der' and `Flip' on Riordan arrays. We fully characterize the Riordan arrays resulting from these operations applied to the Appell and Lagrange subgroups of the Riordan group. Finally, we study the application of these operations to various known Riordan arrays, generating many combinatorial identities in the process.

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Caroline Bang, Matias von Bell, Eric Culver, Jessica Dickson, Stoyan Dimitrov, Rachel Perrier, Sheila Sundaram. 2022-10-05. On Sums, Derivatives, and Flips of Riordan Arrays. https://arxiv.org/abs/2210.02566

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