Title    : A conjecture on B-groups

Author   : Serge Bouc

Abstract : In this note, I propose the following conjecture: a finite group G 
is nilpotent if and only if its largest quotient B-group \beta(G) is nilpotent.
I give a proof of this conjecture under the additional assumption that G be 
solvable. I also show that this conjecture is equivalent to the following: 
the kernel of restrictions to nilpotent subgroups is a biset-subfunctor 
of the Burnside functor.