Bimonster

In mathematics, the Bimonster is a group that is the wreath product of the Monster group M with Z₂:

$Bi = M \wr \mathbb{Z}_2.$

The Bimonster is also a quotient of the Coxeter group corresponding to the Coxeter-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; this was proved in 1990 by A. A. Ivanov and Simon P. Norton.