Smooth skew-morphisms of the dihedral groups
A skew-morphism $φ$ of a finite group $A$ is a permutation on $A$ such that $φ(1)=1$ and $φ(xy)=φ(x)φ^{π(x)}(y)$ for all $x,y\in A$ where $π:A\to\mathbb{Z}_{|φ|}$ is an integer function. A skew-morphism is smooth if $π(φ(x))=π(x)$ for all $x\in A$. The concept of smooth skew-morphisms is a generalization of that of $t$-balanced skew-morphisms. The aim of the paper is to develop a general theory of smooth skew-morphisms. As an application we classify smooth skew-morphisms of the dihedral groups.