In mathematics, the term cosocle (socle meaning pedestal in French) has several related meanings.
In group theory, a cosocle of a group G, denoted by Cosoc(G), is the intersection of all maximal normal subgroups of G.[1] If G is a quasisimple group, then Cosoc(G) = Z(G).
[1] In the context of Lie algebras, a cosocle of a symmetric Lie algebra is the eigenspace of its structural automorphism that corresponds to the eigenvalue +1.
(A symmetric Lie algebra decomposes into the direct sum of its socle and cosocle.
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