Restricted enveloping algebras whose skew and symmetric elements are Lie   metabelian
  Let $L$ be a restricted Lie algebra over a field of characteristic $p>2$ and denote by $u(L)$ its restricted enveloping algebra. We establish when the symmetric or skew elements of $u(L)$ under the principal involution are Lie metabelian. 
Salvatore Siciliano and Hamid Usefi
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