The determination of finite
groups which can be represented as a group of 7 × 7 matrices irreducible
over the complex numbers is finished in this paper. To simplify the cases,
the matrices are assumed unimodular and the groups are primitive. The
groups discussed here are essentially simple and have orders 7 ⋅ 5a⋅ 3b⋅ 2c.
The theory of groups with a prime to the first power in the group order
and of course the representation of degree seven are used heavily in the
determination.