Geometric Correction for Diffusive Expansion of Steady Neutron Transport   Equation
  We revisit the diffusive limit of a steady neutron transport equation in a $2$-D unit disk with one-speed velocity. We show the classical result in [4] with Milne expansion is incorrect in $L^{\infty}$ and we give the right answer in studying the $\epsilon$-Milne expansion with geometric correction. 
Lei Wu and Yan Guo
math.AP