title: Moment isotropy and discrete rotational symmetry of two-dimensional lattice vectors.
abstract: We present a direct proof of a theorem linking the order of moment isotropy and degree of discrete rotational symmetry for a two-dimensional set of lattice vectors. This theorem has been proved previously based on properties of sinusoidal functions. The new proof is based instead on purely linear algebraic arguments.
authors.affiliation: Exa Corporation, 55 Network Drive, Burlington, MA 01803, USA. hudong@exa.com
authors.forename: Hudong
authors.initials: H
authors.lastname: Chen
authors.forename: Steven
authors.initials: S
authors.lastname: Orszag