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比利时vs摩洛哥足彩 ,
university of california san diego

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math 209 - number theory

zev klagsbrun

center for communications research

the joint distribution of $\operatorname{sel}_\phi{(e^d/{\mathbb{q}})}$ and $\operatorname{sel}_{\hat\phi}{(e^{\prime d}/{\mathbb{q}})}$ in quadratic twist families

abstract:

we show that the $\phi$-selmer ranks of twists of an elliptic curve $e$ with a point of order two are distributed like the ranks of random groups in a manner consistent with the philosophy underlying the cohen-lenstra heuristics. if $e$ has a point of order two, then the distribution of $dim_{\mathbb{f}_2} \operatorname{sel}_\phi{(e^d/{\mathbb{q}})} - dim_{\mathbb{f}_2} \operatorname{sel}_{\hat\phi}{(e^{\prime d}/{\mathbb{q}})}$ tends to the discrete normal distribution $\mathcal{n}(0,\frac{1}{2} \log \log x)$ as $x \rightarrow \infty$. we consider the distribution of $dim_{\mathbb{f}_2} \operatorname{sel}_\phi{(e^d/{\mathbb{q}})} - dim_{\mathbb{f}_2} \operatorname{sel}_{\hat\phi}{(e^{\prime d}/{\mathbb{q}})}$ has a fixed value $u$. we show that for every $r$, the limiting probability that $dim_{\mathbb{f}_2} \operatorname{sel}_\phi{(e^d/{\mathbb{q}})}= r$ is given by an explicit constant $\alpha_{r,u}$ introduced in cohen and lenstra's original work on the distribution of class groups.

host: kiran kedlaya

may 26, 2016

2:00 pm

ap&m 7321

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