On a new criterion to decide whether a spline space can be used for design
Résumé
The splines we investigate are piecewise Chebyshevian splines, in the sense of splines with pieces taken from different Extended Chebyshev spaces, and they satisfy parametric continuity conditions at the knots. We achieve a criterion to decide whether such splines can be used for geometric design purposes. We also give a few illustrations to indicate how to use the criterion.