The application of the variational method to neutron transport theory

Two distinct ways in which the variational method may be used to obtain approximate solutions of the equations which are involved in neutron transport theory are discussed. In the first, a method is given whereby an estimate of an eigenvalue or some weighted average of the solution of the equation is obtained. Whilst the second way is a method whereby a relatively complicated equation involving multi-dimensional variables is reduced to a number of simpler equations each in a fewer number of independent variables. Examples to illustrate both methods are given.