FVA Not for points Homework / test English to Spanish Science Mathematics & Statistics

Hi everyone!

After a lot of research I can't seem to find what is the equivalent to this term in Spanish.

I have found "ecuación diferencial con retraso o retardo" as a translation to "difference-differential equation" but I doesn't seem like the term "relación diferencial con retraso o retardo" exists, so I have to think they are completely different things even though the adjective is the same.

I also found "relación de recurrencia diferencial" but I can't tell if this is the right term because I can't find any definitions of these terms, or easily understandable explanations. This is advanced Math and I'm desperate. Can anyone help me? I'll be eternally grateful :D

The term appears here:

"Sobolev orthogonal polynomials and the sequence of the semiclassical orthogonal polynomials associated with the linear functional u are obtained. Also, the Sobolev orthogonal polynomials satisfy a difference-differential relation and a 2N+2 order differential equation. The results obtained in this work constitute a straightforward generalization to the non-diagonal case."