On curves intersecting at most once, II

Abstract

We prove that on a closed, orientable surface of genus $g$, a set of simple loops with the property that no two are homotopic or intersect in more than $k$ points has cardinality ${\lesssim }_k{g}^{k+1}\log g$. The bound matches the size of the largest known construction to within a factor of ${\sim }_k\log g$. It generalizes an earlier result of the author, which treated the case $k=1$. The proof blends probabilistic ideas with covering space arguments related to the fact that surface groups are LERF.

10 pages