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
5,047 questions , 2,200 unanswered
5,345 answers , 22,709 comments
1,470 users with positive rep
816 active unimported users
More ...

  Why internal symmetry is always compact and semisimple Lie group up to U(1)?

+ 3 like - 0 dislike
728 views
Why internal symmetry is always compact and semisimple Lie group up to U(1)? Is there internal symmetry non-compact or non-semisimple?
asked Jan 19, 2015 in Closed Questions by Alienware (185 points) [ no revision ]
recategorized Jun 22, 2015 by dimension10

Basically in order to have a positive-definite kinetic term in the Lagrangian, see this post. If you are happy with the answer therein I propose to close the question as duplicate.

The complete answer is given by Stan in the post linked to by Jia Yiyang.





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

Your rights
...