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  1. Erd\H{o}s and Pomerance have shown that $$\varphi(n)$$ typically has about $$\frac{1}{2}(\log\log{n})^2$$ distinct prime factors. More precisely, $$\omega(\varphi(n))$$ has normal order $$\frac{1}{2}(\log\log{n})^2$$. Since $$\varphi(n)$$ is the size of the multiplicative group $$(\Z/n\Z)^{\times}$$, this result also gives the normal number of Sylow subgroups of $$(\Z/n\Z)^{\times}$$. Recently, Pollack considered specifically noncyclic Sylow subgroups of $$(\Z/n\Z)^{\times}$$, showing that the count of those has normal order $$\log\log{n}/\log\log\log{n}$$. We prove that the count of noncyclic Sylow subgroups that are elementary abelian of a fixed rank $$k\ge 2$$ has normal order $$\frac{1}{k(k-1)} \log\log{n}/\log\log\log{n}$$. So for example, (typically) among the primes $$p$$ for which the $$p$$-primary component of $$(\Z/n\Z)^{\times}$$ is noncyclic, this component is $$\Z/p\Z \oplus \Z/p\Z$$ about half the time. Additionally, we show that the count of $$p$$ for which the $$p$$-Sylow subgroup of $$(\Z/n\Z)^{\times}$$ is not elementary abelian has normal order $$2\sqrt{\pi} \sqrt{\log\log{n}}/\log\log\log{n}$$. 
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    Free, publicly-accessible full text available April 1, 2027
  2. In this paper, we express the difference of two complementary Beatty sequences as the sum of two other closely related Beatty sequences. In the process, we introduce a new algorithm that generalizes the well-known Minimum Excluded algorithm and provides a method to combinatorially generate any pair of complementary Beatty sequences in a natural way. 
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    Free, publicly-accessible full text available December 15, 2026