A New Collocation - Type Method for Hammerstein Integral Equations

We consider Hammerstein equations of the form y(i)=f(t)+(hk(t,s)g(s,y(s))ds, te[a,b], J a and present a new method for solving them numerically. The method is a collocation method applied not to the equation in its original form, but rather to an equivalent equation for z(t):= g(t,y(t)). The desired approximation to y is then obtained by use of the (exact) equation y(t)=f(t) + fh k(t,s)z(s)ds, te[a,b]. •'a Advantages of this method, compared with the direct collocation approximation for y, are discussed. The main result in the paper is that, under suitable conditions, the resulting approximation to y converges to the exact solution at a rate at least equal to that of the best approximation to z from the space in which the collocation solution is sought.