Lie algebra Definition and 163 Threads

  1. J

    O(3) sp(2) lie algebra isomorphism problem

    I'm mainly hoping that somebody else might have done the same exercise earlier. In that case it could be possible to spot where I'm going wrong. Homework Statement I'm supposed to prove that Lie algebras \mathfrak{o}(3) and \mathfrak{sp}(2) are isomorphic. Homework Equations Let's...
  2. H

    What is the simplicity of the Special Linear Lie Algebra?

    Hi, Show that the Special linear Lie algebra is simple. I tried it with induction but without result.
  3. J

    Homework EquationsThe Attempt at a SolutionDifficult 3D Lie algebra [SOLVED]

    [SOLVED] Difficult 3D Lie algebra Homework Statement Let \left(\begin{array}{cc} a & b \\ c & d \end{array}\right) \in GL_2(\mathbb{C}). Consider the Lie algebra \mathfrak{g}_{(a,b,c,d)} with basis {x,y,z} relations given by [x,y]= ay + cz [x,z] = by + dz [y,z] = 0 Show that...
  4. W

    Which Book on Lie Groups and Lie Algebras is a Classic?

    I'm looking for a solid book on Lie groups and Lie algebras, there is too many choices out there. What is a classic text, if there is one?
  5. L

    Semi-Simple Lie Algebra Representations

    I'm trying to prove that any representation of a semisimple Lie algebra can be uniquely decomposed into irreducible representations. I have seen some sketches of proofs that show that any representation \phi of a semisimple Lie algebra which acts on a finite-dimensional complex vector space...
  6. L

    Lie Algebra: Why is 2D Nilpotent Lie Algebra Abelian?

    I read in Knapp's book on Lie algebras that "a 2-dimensional nilpotent Lie algebra is abelian." Why is this the case? Can somebody who knows please tell me?
  7. J

    Lie algebra, ideal and isomorphism

    Suppose A\subset\mathfrak{g} and I\subset\mathfrak{g} are subalgebras of some Lie algebra, and I is an ideal. Is there something wrong with an isomorphism (A+I)/I \simeq A/I, a+i+I=a+I\mapsto a+I, for a\in A and i\in I? I cannot see what could be wrong, but all texts always give a theorem...
  8. Fredrik

    Proving Equivalence of Lie Bracket Definitions for Lie Groups

    I'm reading about gauge theory and the text goes through some stuff about Lie groups and algebras rather quickly. I tried to prove one of the things they state without proof and got stuck. Suppose that M and N are manifolds and \phi:M\rightarrow N is a diffeomorphism. Then we can define a...
  9. E

    Can L Be Isomorphic to sl(2,C)?

    Homework Statement Take L = \left(\begin{array}{ccc}0 & -a & -b \\b & c & 0 \\a & 0 & -c\end{array}\right) where a,b,c are complex numbers. Homework Equations I find that a basis for the above Lie Algebra is e_1 = \left(\begin{array}{ccc}0 & -1 & 0 \\0 & 0 & 0 \\1 & 0 &...
  10. M

    Structure constants of Lie algebra

    The following matrices are written in Matlab codes form. The standard basis for so(3) is: L1 = [0 0 0; 0 0 -1; 0 1 0], L2 = [0 0 1; 0 0 0; -1 0 0], L3 = [0 -1 0; 1 0 0; 0 0 0]. Since [L1, L2] = L3, the structure constants of this Lie algebra are C(12, 1) = C(12, 2) = 0, C(12, 3) = 1...
  11. S

    Struggling to understand Lie Algebra: Constructing Weight Diagrams

    Hi, I have spent all weekend reading Textbooks, where I concentrated on Cahn, trying to understand what is going on in Lie Algebra lecture notes. I am having a lot of trouble because I have no background in maths other than applied maths, and lie algebras is so different to applied maths and I...
  12. D

    How can I calculate the Killing form of a Lie algebra using a specific basis?

    OK, firstly I hope this is the rigth place for my question. I'm in a bit of a problem. I need to be able to calucalte the Killing for for a Lie algebra by next wek, but I'm stuck and won't be able to get any help in 'real life' until Friday, not leaving me enough time to sort out my problem. So...
  13. D

    Does 0 Belong to the Center of a Lie Algebra?

    OK, can someone please tell if 0 (zero) would belong to the center of a Lie algebra. By center I mean for a Lie algebra L center(L) = { z in L : [z,x]=0 for all x in L} I think it should, but I'm not too sure...I'm surely confusing myself somewhere along the line, as this shouldn't be...
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