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Take a vector space $V={A,B,C,...}$ (of matrices), and the commutator $[A,B]=AB-BA$, then a Lie algebra of $V$ is characterized by $[V,V]$ staying in $V$. (Loosely speaking.)

What happens when you replace the commutator with some other thing (based on matrix products), again presupposing that the result stays in $V$? With the anticommutator you get Jordan algebras, so at least there are interesting alternatives. Take the most general form with "product dimension" two:
$<A,B>=f_1*AA+f_2*AB+f_3*BA+f_4*BB$
Has the resulting algebra already been researched (or is it pointless for whatever algebraic reason)? In both cases, a reference would come in handy.

If you go to "dimension 3", the most obvious form of a "commutritor" would be
$<A,B,C>=ABC+BCA+CAB-ACB-BAC-CBA$
Again, I'd like to know either a reference or a reason why this is no useful idea. (Surely someone had that idea before me!)

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  • $\begingroup$ You mean something like this mathoverflow.net/questions/96584/ternary-lie-structure ? $\endgroup$
    – UwF
    Commented Feb 21, 2014 at 16:22
  • $\begingroup$ This question seems basically clear to me -- I'm not sure why it was put on hold. $\endgroup$
    – arsmath
    Commented Feb 24, 2014 at 14:29
  • $\begingroup$ Some of these have been studied, though I don't know how general of a theory there is. Non-associative products of the form AB + c BA show up as "noncommutative Jordan algebras". There is a ternary generalization of Jordan algebras that's commonly studied because it behaves better in characteristic 2 than the usual definition. There are some other ternary generalizations that are discussed in the first chapter of McCrimmon's book on Jordan algebras. $\endgroup$
    – arsmath
    Commented Feb 24, 2014 at 14:33
  • $\begingroup$ @arsmath To see why it was put on hold, check the edit history. $\endgroup$ Commented Feb 24, 2014 at 14:37
  • $\begingroup$ @TobiasKildetoft - Thanks, you're completely right. I should have done that before shooting my big mouth off. Er, big keyboard off? $\endgroup$
    – arsmath
    Commented Feb 24, 2014 at 15:06

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