These observations allow one to formalize the definition of reflection: a reflection is an involutive isometry of an Euclidean space whose set of fixed points is an affine subspace of codimension 1.
这些观察允许我们形式化反射的定义: 反射是欧里得空的对合等距同构,它的不点集合是余维度为 1 的仿射子空。