I'm doing a project for my quantu class on the non-relativistic path integral formulation. I took out "quantum mechanics and path integrals" feynmann, but he doesn't seem to like explaining explicitly how certain results are obtained.... so my two main questions are should the weight function exp[i/h S] be computed between the time of first measurement and the time of second measurement? and also how do you put the integral into terms of x1,x2,x3...... I don't really understand how these are defined, in the book he seemed to be describing them as points for a riemann sum but then he wrote an integral with respect to all of them and I got lost. do you merely commput the action for some path x1(t) integrate and then attempt to integrate then multiply it by the weight function comuted for x2 and integrate with respect to x2 and simply continue this process until your done?