Let E be a real Banach space. A norm-one element e in E is said to be an isometric reflection vector if there exist a maximal subspace M of E and a linear isometry F : E → E fixing the elements of M ...

We humans have always had a fascination with the circle. We experience it throughout nature—in the spiral of the Milky Way, the orbiting planets, and the cycles of life itself. As children, we also ...