Dear Roberto, 

   I have a question about extrapolation operators in PPL library, in general, they don't guarantee termination, right?  Then, I found the following text from the documentation:

"Note that a convergence guarantee can only be obtained by suitably restricting the set of constraints that can occur in this additional parameter. "

Here is my question:

Do they guarantee termination if I have a fixed set (any) of constraints? or the set of constraints has to be carefully chosen?

Many thanks in advance :)

Best 

Bishoksan