PROBLEM 2.6

We shall demonstrate how to derive the compatibility relation between G and D. The reader should repeat the calculation for the remaining compatibility relations.

First we need to find the operations of G which are also symmetry operations in the group of D . From Table 2. 13 we find the following correspondence:
Operation in G  Corresponding Operation in D
{E} {E}
{C2} {C24
{s} {md}
{s'} {md'}
By definition on page 45, two representations are compatible if they have the same characters for the corresponding classes according to the above table. Based on this definition clearly G1 is compatible with D1 while G2 is compatible with D2.

For G3 the characters for the above 4 classes are:
{E} {C2 {s} {s'}
G3 2 0 0
From Table 2.14 we see that the characters of D1+D2 are exactly the same for the corresponding classes:
{E} {C24 {md} {md'} 
D1+D2 2 0 0
It should be a straight forward exercise to show the remaining compatibility relations between Gand D.