Multistring based matrices

Abstract

A virtual $n$-string is a chord diagram with $n$ core circles and a collection of arrows between core circles. We consider virtual $n$-strings up to virtual homotopy, compositions of flat virtual Reidemeister moves on chord diagrams. Given a virtual 1-string $\alpha$, Turaev associated a based matrix that encodes invariants of the virtual homotopy class of $\alpha$. We generalize Turaev's method to associate a multistring based matrix to virtual $n$-strings, addressing an open problem of Turaev and constructing similar invariants for virtual homotopy classes of virtual $n$-strings.