Hecke algebra
For m∈ℕ, let Tmf(z)=∑∞n=0bnqn with :
bn=∑d|gcd(m,n)dk-1amn/d2 | (2) |
In particular, for p a prime, Tpf(z)=∑∞n=0bnqn with;
bn=apn+pk-1an/p | (3) |
where an/p=0 if n is not divisible by p.
The operator Tn is a linear operator on the space of modular forms called a Hecke operator.
The Hecke operators leave the space of modular forms and cusp forms invariant
and turn out to be self-adjoint
for a scalar product
called the Petersson
scalar product. In particular they have real eigenvalues
. Hecke operators
also satisfy multiplicative properties that are best summarized by the formal
identity
:
∞∑n=1Tnn-s=∏𝑝(1-Tpp-s+pk-1-2s)-1 | (4) |
That equation in particular implies that TmTn=TnTm whenever gcd(n,m)=1.
The set of all Hecke operators is usually denoted 𝕋 and is called the Hecke algebra.
0.1 Group algebra example
Definition 0.1 Let Glcd be a locally compact totally disconnected group; then the Hecke algebra H(Glcd) of the group Glcd is defined as the convolution algebra of locally constant complex-valued functions on Glcd with compact support.
Such ℋ(G) algebras play an important role in the theory of
decomposition of group representations
into tensor products
.
Title | Hecke algebra |
---|---|
Canonical name | HeckeAlgebra |
Date of creation | 2013-03-22 14:08:13 |
Last modified on | 2013-03-22 14:08:13 |
Owner | olivierfouquetx (2421) |
Last modified by | olivierfouquetx (2421) |
Numerical id | 13 |
Author | olivierfouquetx (2421) |
Entry type | Definition |
Classification | msc 11F11 |
Classification | msc 20C08 |
Related topic | ModularForms |
Related topic | AlgebraicNumberTheory |
Defines | Hecke operator |
Defines | Hecke algebra H(G) of the group G |