Back to Degree 2, Back to the start
Let
denote the Legendre symbol mod 3.
There is a weight 1 Eisenstein series in
which is associated with
It is given by
In general, we use the notation
where
denotes the level 1 Eisenstein series of weight k.
The square of
is the Eisenstein series of weight 2:
which is associated with
There is a two dimensional space of modular forms of weight 4 spanned by
and
Other relations among Eisenstein series include:
and