Before revision: For mathematical details see Direct product of groups The concept of a In applied mathematics, double groups are groups composed of rotations and related transformations, employed particularly in the field of physical chemistry.
After revision: The character tables of the binary tetrahedral, octahedral and icosahedral groups following Frobenius (1899) In applied mathematics, double groups are groups composed of rotations and related transformations, employed particularly in the field of physical chemistry.