-adic analysis and Bell numbers of two variables. (Analyse -adique et nombres de Bell à deux variables.)
Let and be the -th Padovan and Perrin numbers respectively. Let be non-zero integers with and , let be the generalized Lucas sequence given by , with and In this paper, we give effective bounds for the solutions of the following Diophantine equations where , and are non-negative integers. Then, we explicitly solve the above Diophantine equations for the Fibonacci, Pell and balancing sequences.
We answer the question posed by Ian Stewart which Padovan numbers are at the same time Fibonacci numbers. We give a result on the difference between Padovan and Fibonacci numbers, and on the growth of Padovan numbers with negative indices.
In his proof of Szemerédi’s Theorem, Gowers introduced certain norms that are defined on a parallelepiped structure. A natural question is on which sets a parallelepiped structure (and thus a Gowers norm) can be defined. We focus on dimensions and and show when this possible, and describe a correspondence between the parallelepiped structures and nilpotent groups.