• 検索結果がありません。

Problem 1. Let G be a finite group, and let G b be the set of isomorphism classes of irreducible finite dimensional complex representations of G. For every σ ∈ G, we b choose a representative (V

N/A
N/A
Protected

Academic year: 2021

シェア "Problem 1. Let G be a finite group, and let G b be the set of isomorphism classes of irreducible finite dimensional complex representations of G. For every σ ∈ G, we b choose a representative (V"

Copied!
1
0
0

読み込み中.... (全文を見る)

全文

(1)

Algebra III/Introduction to Algebra III: Representation Theory Due: Please upload solutions to NUCT by Tuesday, June 16, 2020.

Problem 1. Let G be a finite group, and let G b be the set of isomorphism classes of irreducible finite dimensional complex representations of G. For every σ ∈ G, we b choose a representative (V

σ

, π

σ

) of the class σ. We define the Fourier transform of f ∈ C [G] to be the “function”

1

f b that to σ ∈ G b assigns the endomorphism

f b (σ) = X

g∈G

f (g)π

σ

(g) ∈ End

C

(V

σ

).

Prove the following statements:

(a) For all f

1

, f

2

∈ C [G] and σ ∈ G, b

f \

1

∗ f

2

(σ) = f b

1

(σ) ◦ f b

2

(σ),

where f

1

∗ f

2

∈ C [G] is the convolution product of f

1

and f

2

defined by (f

1

∗ f

2

)(g) = X

hk=g

f

1

(h)f

2

(k).

Here the sum ranges over pairs (h, k) ∈ G × G such that hk = g.

(b) For all f ∈ C [G], the Frobenius inversion formula f (g) = 1

|G|

X

σ∈Gb

n

σ

tr(π

σ

(g)

−1

◦ f b (σ))

holds. Here n

σ

= dim

C

(V

σ

) and we recall that |G| = P

σ∈Gb

n

2σ

.

1The Fourier transformfbis really not a function, but rather a section of a bundle, where the fiber ofσ is EndC(Vσ). Also, to avoid making the choice of (Vσ, πσ), one should work with the

∞-category of representations instead.

1

参照

関連したドキュメント

As with M¨ obius groups, we define the limit set L(G) of the convergence group G to be the set of all limit points of those sequences { f n } converging in the sense of (ii)..

Thus as a corollary, we get that if D is a finite dimensional division algebra over an algebraic number field K and G = SL 1,D , then the normal subgroup structure of G(K) is given

Let X be an admissible Riemannian complex and G be a finitely generated group with with polynomial volume growth such that X/G = Y is a finite polytopal complex satisfying

The objective of this paper is to apply the two-variable G /G, 1/G-expansion method to find the exact traveling wave solutions of the following nonlinear 11-dimensional KdV-

Given a compact Hausdorff topological group G, we denote by O(G) the dense Hopf ∗-subalgebra of the commutative C ∗ -algebra C(G) spanned by the matrix coefficients of

A remarkable feature of irreducible affine isometric actions of a locally compact group G is that they remain irreducible under restriction to “most” lattices in G (see [Ner,

Let G be a split reductive algebraic group over L. In what follows we assume that our prime number p is odd, if the root system Φ has irreducible components of type B, C or F 4, and

In analogy with Aubin’s theorem for manifolds with quasi-positive Ricci curvature one can use the Ricci flow to show that any manifold with quasi-positive scalar curvature or