4 papers
Biquandle (co)homology and handlebody-links
Atsushi Ishii, Masahide Iwakiri, Seiichi Kamada +3
In this paper, we introduce the (co)homology group of a multiple conjugation biquandle. It is the (co)homology group of the prismatic chain complex, which is related to the homolog…
Up-down colorings of virtual-link diagrams and the necessity of Reidemeister moves of type II
Kanako Oshiro, Ayaka Shimizu, Yoshiro Yaguchi
We introduce an up-down coloring of a virtual-link diagram. The colorabilities give a lower bound of the minimum number of Reidemeister moves of type II which are needed between tw…
A multiple conjugation biquandle and handlebody-links
Atsushi Ishii, Masahide Iwakiri, Seiichi Kamada +3
We introduce a multiple conjugation biquandle, and show that it is the universal algebra to define a semi-arc coloring invariant for handlebody-links. A multiple conjugation biquan…
Symmetric Extensions of Dihedral Quandles and Triple Points of Non-orientable Surfaces
J. Scott Carter, Kanako Oshiro, Masahico Saito
Quandles with involutions that satisfy certain conditions, called good involutions, can be used to color non-orientable surface-knots. We use subgroups of signed permutation matric…