  We investigate the universal linear inequalities that hold for the von
Neumann entropies in a multi-party system, prepared in a stabiliser state. We
demonstrate here that entropy vectors for stabiliser states satisfy, in
addition to the classic inequalities, a type of linear rank inequalities
associated with the combinatorial structure of normal subgroups of certain
matrix groups.
  In the 4-party case, there is only one such inequality, the so-called
Ingleton inequality. For these systems we show that strong subadditivity, weak
monotonicity and Ingleton inequality exactly characterize the entropy cone for
stabiliser states.
