Daniel Krenn

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Efficient scalar multiplication in Abelian groups (which is an important operation in public key cryptography) can be performed using digital expansions. Apart from rational integer bases (double-and-add algorithm), imaginary quadratic integer bases are of interest for elliptic curve cryptography, because the Frobenius endomorphism fulfils a quadratic(More)
For fixed t ≥ 2, we consider the class of representations of 1 as sum of unit fractions whose denominators are powers of t or equivalently the class of canonical compact t-ary Huffman codes or equivalently rooted t-ary plane “canonical” trees. We study the probabilistic behaviour of the height (limit distribution is shown to be normal), the number of(More)
1IT University of Copenhagen, Denmark, maau@itu.dk 2Institut für Theoretische Informatik, Technische Universität Ilmenau, Germany, martin.dietzfelbinger@tu-ilmenau.de 3Institut für Mathematik, Alpen-Adria-Universität Klagenfurt, Austria, clemens.heuberger@aau.at 4Institut für Mathematik, Alpen-Adria-Universität Klagenfurt, Austria, math@danielkrenn.at or(More)
For a fixed integer base $$b\ge 2$$ b ≥ 2 , we consider the number of compositions of 1 into a given number of powers of b and, related, the maximum number of representations a positive integer can have as an ordered sum of powers of b. We study the asymptotic growth of those numbers and give precise asymptotic formulae for them, thereby improving on(More)
For fixed t ≥ 2, we consider the class of representations of 1 as sum of unit fractions whose denominators are powers of t or equivalently the class of canonical compact t-ary Huffman codes or equivalently rooted t-ary plane “canonical” trees. We study the probabilistic behaviour of the height (limit distribution is shown to be normal), the number of(More)
We present an average case analysis of a variant of dual-pivot quicksort. We show that the used algorithmic partitioning strategy is optimal, i.e., it minimizes the expected number of key comparisons. For the analysis, we calculate the expected number of comparisons exactly as well as asymptotically, in particular, we provide exact expressions for the(More)