Bimonster group

In mathematics, the bimonster is a group that is the wreath product of the monster group M with Z₂:

The Bimonster is also a quotient of the Coxeter group corresponding to the Dynkin diagram Y₅₅₅, a Y-shaped graph with 16 nodes:

John H. Conway conjectured that a presentation of the bimonster could be given by adding a certain extra relation to the presentation defined by the Y₅₅₅ diagram; this was proved in 1990 by A. A. Ivanov and Simon P. Norton.