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Periodicity and almost-periodicity. Appendix by Imre Z. Ruzsa. (English) Zbl 1103.68103

Győri, Ervin (ed.) et al., More sets, graphs and numbers. A salute to Vera Sós and András Hajnal. Berlin: Springer. Budapest: János Bolyai Mathematical Society (ISBN 3-540-32377-5/hbk). Bolyai Society Mathematical Studies 15, 381-405 (2006).
Summary: Periodicity and almost-periodicity are phenomena which play an important role in most branches of mathematics and in many other sciences. This is a survey paper on my work in this area and on related work. I restrict myself to periodicity questions in combinatorics on words (the main dish), but I start with a periodicity problem from number theory (the entree) and at the end there is an Appendix by Imre Ruzsa containing a partial answer to one of my problems (the dessert). Sections 1–10 concern one-dimensional results and open problems. Sections 11–16 deal with multi-dimensional analogues. I do not claim completeness in any sense.
For the entire collection see [Zbl 1086.05003].

MSC:

68R15 Combinatorics on words
11B75 Other combinatorial number theory
05B45 Combinatorial aspects of tessellation and tiling problems