Residue-class-wise affine group
In mathematics, specifically in group theory, residue-class-wise affine groups are certain permutation groups acting on Z {\displaystyle \mathbb {Z} } (the integers), whose elements are bijective residue-class-wise affine mappings. A mapping f : Z → Z {\displaystyle f:\mathbb {Z} \rightarrow \mathbb {Z} } is called residue-class-wise affine if there is a nonzero integer m {\displaystyle m} such that the restrictions of f {\displaystyle f} to the residue classes (mod m {\displaystyle m} ) are all affine.
Source: Wikipedia — Residue-class-wise affine group (CC BY-SA 4.0)