M. Linckelmann
A note on the Schur multiplier of a fusion system

Abstract.
The Schur multiplier of a fusion system $\mathcal F$ on a finite
$p$-group $P$, being defined as the inverse limit of the Schur
multipliers of the subgroups of $P$ taken over the category 
$\mathcal F$, has a series of properties analogous to some 
properties of Schur multipliers of finite groups. This is one
of the tools used in Kessar [3] to show that the Solomon fusion
system cannot arise as the Brauer category of a $p$-block of
a finite group.