Spinor formulation of the general 20-dimensional Gel'fand-Yaglom wave equation based on the representation (1/2, 3/2)+(-1/2, 3/2)+(1/2, 5/2)+(-1/2, 5/2)+(1/2, 3/2)+(-1/2, 3/2)

The general 20-dimensional Gel'fand-Yaglom wave equation is reformulated in spinor form and a method is given of obtaining the subsidiary conditions of the second kind in the presence of an external electomagnetic field. These equations form a class which is defined by a set of simultaneous equations that is not empty