Normal modes can be computed by stepping through a descending sequence of one type of these objects via successive atom substitutions, and reading a correlation table. Volume A of the International Tables for Crystallography is a list of one type of these objects. (-5[1])Mulliken symbols like A1 and B2 (-5[1])are used to label the rows of 2D diagrams whose columns correspond to elements of these objects. (-5[1])S·A·L·Cs transform with the irreps of these objects. Whether a molecule is IR or Raman-active can be read from the (*) character table for one of these objects. (10[2])Examples of these (10[1])objects like C-sub-infinity (10[2]-5[1])and (10[1])T-sub-d (10[1])respectively describe (10[1])linear and tetrahedral molecules, and are built up from elements (-5[1])like axes of rotation and planes of reflection. For 10 points, (-5[1])“point” examples (10[1])of what (10[1])algebraic objects describe (10[1])the symmetries of molecules? (10[1])■END■ (10[4]0[10])