DJ Katz, KR O'Connor, K Pacheco… - arXiv preprint arXiv …, 2023 - arxiv.org
Let $ F $ be a finite field, let $ f $ be a function from $ F $ to $ F $, and let $ a $ be a nonzero
element of $ F $. The discrete derivative of $ f $ in direction $ a $ is $\Delta_a f\colon F\to F …