Dear all, Sorry for the bad use of the list I did; I'm very young, only 4 days old to this list :-) Thanks a lot for your help and your hints: At 09.01 06/10/03 +0200, you wrote: > mono.con(mgcv) Monotonicity constraints for a cubic > regression spline. That is what I was looking for. It was under my eyes... Thank you for your help. Best, Alessandro