2 problems

Let $A,B,C,D$ be four non-overlapping unit balls in $\mathbb{R}^3$. A geometric permutation is the order in which a line transversal meets the balls. Incompatibility conjecture. Th…

Let $d\geq 1$, and consider a family of pairwise disjoint equal-radius closed balls in $\mathbb{R}^d$. A geometric permutation is the order in which a line transversal meets the ba…