3
votes
0answers
174 views

closure properties of q-differential equations

I am interested in q-differential equations of the form $p(f(z), f(qz),\dots,f(q^kz))=0$ where $p$ is a polynomial and $k$ an nonnegative integer. I wonder about the closure properties of the class ...
5
votes
1answer
703 views

beyond differentially algebraic power series

In a recent question, we learned about the existence of functions that do not satisfy any algebraic differential equation. One nice property of such equations is that there is a good way to ...
12
votes
6answers
781 views

An example of a series that is not differentially algebraic?

Motivated by this question, I remembered a question I was curious about sometime which I am sure has some easy and nice example for it as well, which I just can't think of for some reason. I want an ...