On irrationality measure functions for several real numbers (Q2165902)

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On irrationality measure functions for several real numbers
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    On irrationality measure functions for several real numbers (English)
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    23 August 2022
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    For a real irrational number \(\zeta\) we define irrational measure \(\psi_\zeta(t)=\min_{1\leq q\leq t, q\in\mathbb Z}\Vert q\zeta\Vert\), where \(\Vert \cdot \Vert\) denotes the distance to the nearest integer. We call two real irrational numbers \(\alpha\) and \(\beta\) independent iff \(\psi_\alpha(t) \not= \psi_\beta(t)\). Let \(\alpha =(\alpha_1,\dots ,\alpha_n)\) be a \(n\)-tuple pairwise real irrational independent numbers. For a large enough \(t\) we have a well-defined permutation \(\sigma(t): \{ 1,\dots ,n\}\to \{\sigma_1,\dots \sigma_n\}\) with \(\psi_{\alpha_1}(t)>\psi_{\alpha_2}(t)>\dots \psi_{\alpha_n}(t)\). Let \(T(\alpha)\) be the maximum \(k\) when there exists different permutation \(\sigma_1,\dots ,\sigma_k\) of the numbers \(1,\dots ,k\) such that for all \(j\in\{ 1,\dots ,k\}\) and \(t_0>0\) there exists \(t>t_0\) such that \(\sigma(t)=\sigma_j\). Then the author proves that \(n\leq \frac 12 T(\alpha)(T(\alpha)+1)\).
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    irrationality measure function
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    independence of real irrational numbers
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    index of independence of real irrational numbers
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