  In math.AG/0005152 a certain $t$-structure on the derived category of
equivariant coherent sheaves on the nil-cone of a simple complex algebraic
group was introduced (the so-called perverse $t$-structure corresponding to the
middle perversity). In the present note we show that the same $t$-structure can
be obtained from a natural quasi-exceptional set generating this derived
category. As a consequence we obtain a bijection between the sets of dominant
weights and pairs consisting of a nilpotent orbit, and an irreducible
representation of the centralizer of this element, conjectured by Lusztig and
Vogan (and obtained by other means in math.RT/0010089).
