An upper bound of the numbers of minimally intersecting filling coherent pairs

Abstract

Let $S_g$ denoting the genus $g$ closed orientable surface. An {\em origami} (or flat structure) on $S_g$ is obtained from a finite collection of unit Euclidean squares by gluing each right edge to a left one and each top edge to a bottom one. Coherent filling pairs of simple closed curves, $(\alpha ,\beta )$ in $S_g$ are pairs for which their minimal intersection is equal to their algebraic intersection. And, a minimally intersecting filling of $(\alpha ,\beta )$ in $S_g$ is a pair whose intersection number is the minimal among all filling pairs of $S_g$. A coherent pair of curves is naturally associated with an origami on $S_g$, and a minimally intersecting filling coherent pair of curves has the smallest number of squares in all origamis on $S_g$. Our main result introduce an algorithm to count the numbers of minimal filling pairs on $S_g$, and establish a new upper bound of this count using Ménage Problem.