Integral Equations of Immunology The inversion of a particular integral equation of the first (Fredholm) kind is the basic problem considered. The strategy which yielded success consisted of three essential points: (1) fit the known experimental data by a curve with properties which derive from properties of the (as yet unknown) function; (2) stabilize the computation for the unknown function by using singular value decomposition; (3) constrain the unknown function approximation (since it represents a probability distribution) to be nonnegative. A number of test cases are presented. One set of actual experimental data is analyzed with the procedures presented. CACM October, 1972 Hanson, R. J. integral equations of the first kind, nonnegative constraints, singular value analysis 3.10 5.14 5.18 5.41 CA721003 JB January 27, 1978 3:37 PM 2275 5 2275 2275 5 2275 2275 5 2275