2.II.19G

Representation Theory | Part II, 2008

A finite group GG of order 360 has conjugacy classes C1={1},C2,,C7C_{1}=\{1\}, C_{2}, \ldots, C_{7} of sizes 1,45,40,40,90,72,721,45,40,40,90,72,72. The values of four of its irreducible characters are given in the following table.

C1C2C3C4C5C6C7512110080110(15)/2(1+5)/280110(1+5)/2(15)/210211000\begin{array}{ccccccc} C_{1} & C_{2} & C_{3} & C_{4} & C_{5} & C_{6} & C_{7} \\ 5 & 1 & 2 & -1 & -1 & 0 & 0 \\ 8 & 0 & -1 & -1 & 0 & (1-\sqrt{5}) / 2 & (1+\sqrt{5}) / 2 \\ 8 & 0 & -1 & -1 & 0 & (1+\sqrt{5}) / 2 & (1-\sqrt{5}) / 2 \\ 10 & -2 & 1 & 1 & 0 & 0 & 0 \end{array}

Complete the character table.

[Hint: it will not suffice just to use orthogonality of characters.]

Deduce that the group GG is simple.

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