Hi all, I would like to ask for the geometric interpretation of the riemann-stieltjies integral. Suppose we have an integral, (integrate f dg) over the interval [a,b], where g is monotonically increasing. Can i interpret it as the area between f and the g function? Moreover, i am a little confused on what do they mean when they say f is integrable with respect to the g function. E.g. (integrate f dg). Do they treat g(x) as a function, g(x)= y and then (integrate f (y) dy) ?