A Capture Problem in Brownian Motion and Eigenvalues of Spherical   Domains
  We resolve a question of Bramson and Griffeath by showing that the expected capture time of four independent Brownian predators pursuing one Brownian prey on a line is finite. Our main tool is an eigenvalue estimate for a particular spherical domain, which we obtain by a coning construction and domain perturbation. 
Jesse Ratzkin and Andrejs Treibergs