B-theorem

In mathematics, the B-theorem is a result in finite group theory formerly known as the B-conjecture.

The theorem states that if $C$ is the centralizer of an involution of a finite group, then every component of $C/O(C)$ is the image of a component of $C$ .¹

References

Gorenstein, Daniel (1983). The Classification of finite simple groups. New York: Plenum Press. p. 7. ISBN 978-0-306-41305-6.