## Hokkaido Mathematical Journal

### Elliptic surfaces and contact conics for a 3-nodal quartic

#### Abstract

Let ${\mathcal Q}$ be an irreducible $3$-nodal quartic and let ${\mathcal C}$ be a smooth conic such that ${\mathcal C} \cap {\mathcal Q}$ does not contain any node of ${\mathcal Q}$ and the intersection multiplicity at $z \in {\mathcal C} \cap {\mathcal Q}$ is even for each $z$. In this paper, we study geometry of ${\mathcal C} + {\mathcal Q}$ through that of integral sections of a rational elliptic surface which canonically arises from ${\mathcal Q}$ and $z \in {\mathcal C} \cap {\mathcal Q}$. As an application, we construct Zariski pairs $({\mathcal C}_1 + {\mathcal Q}, {\mathcal C}_2 + {\mathcal Q})$, where ${\mathcal C}_i$ $(i = 1, 2)$ are smooth conics tangent to ${\mathcal Q}$ at four distinct points.

#### Article information

Source
Hokkaido Math. J., Volume 47, Number 1 (2018), 223-244.

Dates
First available in Project Euclid: 13 March 2018

https://projecteuclid.org/euclid.hokmj/1520928068

Digital Object Identifier
doi:10.14492/hokmj/1520928068

Mathematical Reviews number (MathSciNet)
MR3773733

Zentralblatt MATH identifier
06853599

#### Citation

TUMENBAYAR, Khulan; TOKUNAGA, Hiro-o. Elliptic surfaces and contact conics for a 3-nodal quartic. Hokkaido Math. J. 47 (2018), no. 1, 223--244. doi:10.14492/hokmj/1520928068. https://projecteuclid.org/euclid.hokmj/1520928068