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Rintaro Kozuma

Publications and source records attributed to Rintaro Kozuma.

2 recordsLinked to original sources

An explicit expression of the Lerch zeta function on maximal domains of holomorphy

We give two results on the Lerch zeta function $Φ(z,\,s,\,w)$. The first is to give an explicit expression providing both the analytic continuation of $Φ$ in $n$-variables $(n \in \{1,\,2,\,3\})$ to maximal domains of holomorphy in $\mathbb{C}^n$ with computable evaluation and an extended formula for the special values of $Φ$ at non-positive integers in the variable $s$. The second is to show that Lerch's functional equation is essentially the same as Apostol's functional equation using the first result.

math.CV↗

Elliptic curves related to cyclic cubic extensions

The aim of this paper is to study certain family of elliptic curves $\{\mathscr{X}_H\}_H$ defined over a number field $F$ arising from hyperplane sections of some cubic surface $\mathscr{X}/F$ associated to a cyclic cubic extension $K/F$. We show that each $\mathscr{X}_H$ admits a 3-isogeny $ϕ$ over $F$ and the dual Selmer group $S^{(\hatϕ)}(\hat{\mathscr{X}_H}/F)$ is bounded by a kind of unit/class groups attached to $K/F$. This is proven via certain rational function on the elliptic curve $\mathscr{X}_H$ with nice property. We also prove that the Shafarevich-Tate group $\text{\cyr X} (\hat{\mathscr{X}_H}/\rat)[\hatϕ]$ coincides with a class group of $K$ as a special case.

math.NT↗