Two-Loop Iteration of Five-Point N=4 Super-Yang-Mills Amplitudes
  We confirm by explicit computation the conjectured all-orders iteration of planar maximally supersymmetric N=4 Yang-Mills theory in the nontrivial case of five-point two-loop amplitudes. We compute the required unitarity cuts of the integrand and evaluate the resulting integrals numerically using a Mellin--Barnes representation and the automated package of ref.~[1]. This confirmation of the iteration relation provides further evidence suggesting that N=4 gauge theory is solvable. 
Z. Bern, M. Czakon, D. A. Kosower, R. Roiban, V. A. Smirnov