On the number of tangencies among 1-intersecting curves

Abstract: Let $\cal C$ be a set of curves in the plane such that no three curves in $\cal C$ intersect at a single point and every pair of curves in $\cal C$ intersect at exactly one point which is either a crossing or a touching point. According to a conjecture of J\'anos Pach the number of pairs of curves in $\cal C$ that touch each other is $O(|{\cal C}|)$. We prove this conjecture for $x$-monotone curves.