Natural sl(2) subalgebras in any* Lie algebra -- Lie algebras 17

[@smolboi9659]

44:01 Bless you lol

[@zikanglei7777]

Just a comment though, at 17:50, to prove ad_h is nilpotent, we can show tr((ad_h)^n)=0 for all n>=1 by induction. (Fact: if T is a linear operator and tr(T^n)=0 for all n>=1, then T is nilpotent.)