Triple point numbers of surface-links and symmetric quandle cocycle invariants

Abstract

For any positive integer $n$, we give a 2–component surface-link $F=F_1\cup F_2$ such that $F_1$ is orientable, $F_2$ is non-orientable and the triple point number of $F$ is equal to $2n$. To give lower bounds of the triple point numbers, we use symmetric quandle cocycle invariants.