How can I prove that why the Killing form for an abelian Lie algebra is $0$? Can you help with suggestions, references, answers?
thanks!
How can I prove that why the Killing form for an abelian Lie algebra is $0$? Can you help with suggestions, references, answers?
thanks!
Just use the definition. For abelian Lie algebra $[x,y]=0$ for any $x, y \in g $. So $ad_xy=0, \forall y \in g$...