Reference [1] presents an efficient and sufficient algorithm to approximate general interpolating
Spline curve which goes through the given set of design-data points by using asymptotic iterative B-spline
curves. Firstly, the given set is considered as the control points of a B-spline, to create the initial approximate
curve, then the iterative grade is built based on the error between the initial approximate curve and given set,
it is used to generate an iterative function sequence to approximate the interpolating function of the cover.
Two theorems were given in reference [1], but didn't get proved. In this text, we give a general proof based
on the preceding context and several other references. In the meantime, numerical experiments further prove
that this algorithm is really simple and valid.
