Layer

Symbol-free definition
The layer of a group (sometimes also called commuting product) is defined in the following equivalent ways:


 * It is the commuting product of all components
 * It is the unique largest semisimple normal subgroup

Definition with symbols
The layer of a group $$G$$, denoted $$E(G)$$ is defined as:

Bigger subgroup-defining functions

 * Generalized Fitting subgroup: The generalized Fitting subgroup of a group is the product of its Fitting subgroup and the layer. In symbols $$F^*(G) = F(G)E(G)$$.