Double coset
Let 
be the subgroup preserving a fixed 
.
Given a fixed Lagrangian submanifold 
, we can also consider
its stabilizer 
. We expect the moduli space of BRST structures
to be given by the double coset:
A point of 
could be denoted 
could be denoted this notation is very natural:
denotes the lagrangian submanifold, {\it i.e.} a point of
, and
means taking the equivalence class modulo
