RIGHT-LEFT EQUIVALENT MAPS OF SIMPLIFIED (2, 0)-TRISECTIONS WITH DIFFERENT CONFIGURATIONS OF VANISHING CYCLES

抄録

Trisection maps are certain stable maps from closed 4-manifolds to R². A simpler but reasonable class of trisection maps was introduced by Baykur and Saeki, called a simplified (g, k)-trisection. We focus on the right-left equivalence classes of simplified (2, 0)-trisections. Simplified trisections are determined by their simplified trisection diagrams, which are diagrams on a genus-two surface consisting of simple closed curves of vanishing cycles with labels. The aim of this paper is to study how the replacement of reference paths changes simplified trisection diagrams up to upper-triangular handle-slides. We show that, for a simplified trisection f satisfying a certain condition, there exist at least two simplified (2, 0)-trisections f' and f" such that f , f' and f" are right-left equivalent to each other but their simplified trisection diagrams are not related by automorphisms of a genus-two surface and upper-triangular handle-slides.