Matthias Eck and Jan Hadenfeld
In the present paper the problem of removing one inner knot from the knot sequence of a B-spline curve is discussed. Doing so, a local (geometric) construction of the new control points from the given ones is first introduced. Then the degrees of freedom appearing in this general construction are determined by minimizing three different norms between the old curve and the new curve. Here the best results are obtained by considering the local (continuous) min-max problem. This solution is based on a variant of the (second) algorithm of Remes.
CAGD 12 (1995), 259-282.