Polyharmonic functions for finite graphs and Markov chains

Thomas Hirschler, Wolfgang Woess*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


On a finite graph with a chosen partition of the vertex set into interior and boundary vertices, a λ-polyharmonic function is a complex function f on the vertex set which satisfies (λ ⋅ I − P)nf(x) = 0 at each interior vertex. Here, P may be the normalised adjacency matrix, but more generally, we consider the transition matrix P of an arbitrary Markov chain to which the (oriented) graph structure is adapted. After describing these “global” polyharmonic functions, we turn to solving the Riquier problem, where n boundary functions are preassigned and a corresponding “tower” of n successive Dirichlet type problems is solved. The resulting unique solution will be polyharmonic only at those points which have distance at least n from the boundary. Finally, we compare these results with those concerning infinite trees with the end boundary, as studied by Cohen, Colonna, Gowrisankaran and Singman, and more recently, by Picardello and Woess.
Original languageEnglish
Title of host publicationFrontiers in Analysis and Probability
Subtitle of host publicationIn the Spirit of the Strasbourg-Zürich Meetings
EditorsNalini Anantharaman, Ashkan Nikeghbali, Michael Th. Rassias
Place of PublicationCham
PublisherSpringer International Publishing AG
ISBN (Print)978-3-030-56408-7
Publication statusPublished - 2020

Fields of Expertise

  • Information, Communication & Computing

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