Symmetric quandle colorings and ribbon concordance

Abstract

A quandle can always trivially color an orientable surface-link. This note shows that the surface-link $10_1^{-1,-1}$ of Yoshikawa's table cannot be colored by a symmetric dihedral quandle of order 4, and explains how this obstructs a generalized ribbon concordance between another link of two projective planes $8_1^{-1,-1}$ that does admit a coloring by the same symmetric dihedral quandle.