Abstract
The classical theory of continued fractions has been widely studied for centuries for its important properties of good approximation, and more recently it has been generalized to p-adic numbers where it presents many differences with respect to the real case. In this paper we investigate periodicity for the p-adic continued fractions introduced by Browkin. We give some necessary and sufficient conditions for periodicity in general, although a full characterization of p-adic numbers having purely periodic Browkin continued fraction expansion is still missing. In the second part of the paper, we describe a general procedure to construct square roots of integers having periodic Browkin p-adic continued fraction expansion of prescribed even period length. As a consequence, we prove that, for every \(n \ge 1\), there exist infinitely many \(\sqrt{m}\in \mathbb {Q}_p\) with periodic Browkin expansion of period \(2^n\), extending a previous result of Bedocchi obtained for \(n=1\).
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Acknowledgements
We thank the anonymous referee for his careful reading and thoughtful feedback regarding our manuscript.
Funding
The three authors are members of the INdAM group GNSAGA. At the time the paper was written, the first author was funded by DISMA, Politecnico di Torino, Dipartimento di Eccellenza MIUR 2018–2022.
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Capuano, L., Murru, N. & Terracini, L. On periodicity of p-adic Browkin continued fractions. Math. Z. 305, 17 (2023). https://doi.org/10.1007/s00209-023-03333-3
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DOI: https://doi.org/10.1007/s00209-023-03333-3