Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

PO is now at the Physics Department of Bielefeld University!

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,082 questions , 2,232 unanswered
5,354 answers , 22,789 comments
1,470 users with positive rep
820 active unimported users
More ...

  Wrong equation in a paper about cosmic topology

+ 4 like - 0 dislike
953 views

I am studying the paper  " Exact Polynomial Eigenmodes for Homogeneous Spherical 3-Manifolds"  (https://arxiv.org/pdf/math/0502566v3.pdf)

I am trying to obtain the polynomials given by the equation (43) on page 19.  I am noting that there is an error in the first and the third polynomials in equation (43).   According with the mentioned paper:

but the correct expressions are

Could you confirm the error and the correct expressions?  Many thanks

asked Oct 12, 2016 in Mathematics by juancho (1,130 points) [ no revision ]

1 Answer

+ 4 like - 0 dislike

$T_8 = T'_{4a}T'_{4b} = ({{{\alpha}^{4}}+{2 i {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}) ({{{\alpha}^{4}}-{2 i {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}) =\\
{{{\alpha}^{8}}+{6 {\alpha}^{4} {\beta}^{4}}}+{{\beta}^{8}}$

and

$T_{12} = \frac {T_{4a}^{'3} + T_{4b}^{'3}}{2} = \frac{{{{{({\alpha}^{4}}+{2 i {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}})^{3}}+{{{{({\alpha}^{4}}-{2 i {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}} )^ {3}}}{2} = \\
{{{{\alpha}^{12}}-{9 {\alpha}^{8} {\beta}^{4}}}-{9 {\alpha}^{4} {\beta}^{8}}}+{{\beta}^{12}}$

while with the missing $\sqrt(3)$ , we get correctly (44) :

$T_8 = T'_{4a}T'_{4b} = ({{{\alpha}^{4}}+{2 i \sqrt{3} {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}) ({{{\alpha}^{4}}-{2 i \sqrt{3} {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}) =\\
{{{\alpha}^{8}}+{14 {\alpha}^{4} {\beta}^{4}}}+{{\beta}^{8}}$

and

$T_{12} = \frac {T_{4\alpha}^{'3} + T_{4\beta}^{'3}}{2} = \frac{{{{{({\alpha}^{4}}+{2 i \sqrt{3} {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}})^{3}}+ {{{{({\alpha}^{4}}-{2 i \sqrt{3} {\alpha}^{2} {\beta}^{2}}}+{{\beta}^{4}}} )^ {3}}}{2} = \\
{{{{\alpha}^{12}}-{33 {\alpha}^{8} {\beta}^{4}}}-{33 {\alpha}^{4} {\beta}^{8}}}+{{\beta}^{12}}$


Idem for the following. I mean the author didn't used the equation with the typo error for the next calculus.

Then it is probably just a well found typo error :) You must write to the author to release a new version.

answered Oct 13, 2016 by igael (360 points) [ revision history ]
edited Oct 13, 2016 by igael

@igael, you are very right.  Many thanks.  All the best.

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
p$\hbar\varnothing$sicsOverflow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
Please complete the anti-spam verification




user contributions licensed under cc by-sa 3.0 with attribution required

Your rights
...