How can the recurrence relations for Eisenstein series G_k(z) be proven?

  • Context: Graduate 
  • Thread starter Thread starter MathematicalPhysicist
  • Start date Start date
  • Tags Tags
    Series
Click For Summary

Discussion Overview

The discussion revolves around proving the recurrence relations for Eisenstein series \( G_k(z) \). Participants are exploring methods and properties related to Eisenstein series, particularly in the context of using the Weierstrass \(\wp\) function and its differential equations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant seeks hints for proving the recurrence relations for \( G_k(z) \) and expresses uncertainty about methods beyond induction.
  • Another participant suggests that a property of Eisenstein series is necessary but does not specify which one.
  • A third participant outlines a proof approach involving the Weierstrass \(\wp\) function and its differential equation, indicating a method to derive the recurrence relations through differentiation and equating powers of \( z \).
  • A later reply acknowledges a prior understanding of the second order differential equation mentioned, reflecting a realization about the simplicity of the task.

Areas of Agreement / Disagreement

The discussion does not reach a consensus, as participants express varying levels of understanding and approaches to the proof, with some uncertainty remaining about the specific properties to utilize.

Contextual Notes

Participants have not fully resolved the assumptions or steps necessary for the proof, and the discussion includes references to specific mathematical functions and their properties without complete elaboration.

MathematicalPhysicist
Science Advisor
Gold Member
Messages
4,662
Reaction score
372
Can someone give me a hint how to show the recurrence relations for [tex]G_k(z)[/tex]
,in wiki it's for the d_n's?

Other than proving it by induction I don't have clue what to do here.

Thanks.
 
Physics news on Phys.org
Obviously I need to use here some property of Eisenstein series, I just need to know which?

Anyone?
:rolleyes:
 
Were talking about the recurrence relation here, right?

I haven't worked out all the details, but here's how the proof is supposed to go:

The Weierstrass [itex]\wp[/itex] function (see here) satisfies the following differential equation:

[tex][\wp'(z)]^2 = 4[\wp(z)]^3 - g_2\wp(z) - g_3[/tex]

where [itex]g_2[/itex] and [itex]g_3[/itex] are the same as defined in the wiki article on Eisenstein series. Differentiate this equation and cancel [itex]\wp'(z)[/itex] to get the second order differential equation

[tex]\wp''(z) = 6[\wp(z)]^2 - \frac{1}{2}g_2[/tex]

Now, as in the Eisenstein series article, we have

[tex]\wp(z) = z^{-2} + z^2 \sum_{k=0}^{\infty}\frac{d_kz^{2k}}{k!} = \frac{1}{z^2} + \sum_{k=1}^{\infty}(2k + 1)G_{2k+2}z^{2k}[/tex]

Differentiate twice and equate like powers of z.
 
I am an idiot, the second ODE you gave me I proved before this task.

I shouldv'e known it would be that easy.

Thanks.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
17
Views
4K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 22 ·
Replies
22
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 33 ·
2
Replies
33
Views
4K