On lifting generalized characters in finite groups

On lifting characters in finite groups

On Finite Groups and Their Characters

The idea of a presidential address seems to require a lecture delivered in the most refined and dignified scientific atmosphere yet understandable to the layman, a lecture which treats a difficult field of mathematics in such a complete manner that the audience has the excitement, the aesthetic enjoyment of seeing a mystery resolved, perhaps only with the slightly bitter feeling, of asking afte...

Characters of Finite Abelian Groups

Example 1.2. The trivial character of G is the homomorphism 1G defined by 1G(g) = 1 for all g ∈ G. Example 1.3. Let G be cyclic of order 4 with generator γ. Since γ4 = 1, a character χ of G has χ(γ)4 = 1, so χ takes only four possible values at γ, namely 1, −1, i, or −i. Once χ(γ) is known, the value of χ elsewhere is determined by multiplicativity: χ(γj) = χ(γ)j . So we get four characters, wh...

Characters of Finite Abelian Groups

When G has size n and g ∈ G, for any character χ of G we have χ(g)n = χ(gn) = χ(1) = 1, so the values of χ lie among the nth roots of unity in S1. More precisely, the order of χ(g) divides the order of g (which divides #G). Characters on finite abelian groups were first studied in number theory, since number theory is a source of many interesting finite abelian groups. For instance, Dirichlet u...

Monomial Characters of Finite Groups

An abundance of information regarding the structure of a finite group can be obtained by studying its irreducible characters. Of particular interest are monomial characters — those induced from a linear character of some subgroup — since Brauer has shown that any irreducible character of a group can be written as an integral linear combination of monomial characters. Our primary focus is the cl...