Fixed points of isometry groups in Euclidean space

In the context of Euclidean space, an isometry is a transformation that preserves distances. This means that if you have two points \( A \) and \( B \) in Euclidean space, an isometric transformation \( T \) will maintain the distance between these points, i.e., \( d(T(A), T(B)) = d(A, B) \), where \( d \) denotes the distance function.