In mathematics, in the area of algebra known as group theory, a more than fifty-year effort was made to answer a conjecture of ( Burnside 1911 ): are all groups of odd order solvable? Progress was made by showing that CA-groups, groups in which the centralizer of a non-identity element is abelian, of odd order are solvable ( Suzuki 1957 ). Further progress was made showing that CN-groups, groups in which the centralizer of a non-identity element is nilpotent, of odd order are solvable ( Feit, Thompson & Hall 1960 ). The complete solution was given in ( Feit & Thompson 1963 ), but further work on CN-groups was done in ( Suzuki 1961 ), giving more detailed information about the structure of these groups. For instance, a non-solvable CN-group G is such that its largest solvable normal subgroup O∞(G) is a 2-group, and the quotient is a group of even order.
Solvable CN groups include
Non-solvable CN groups include: