Phase diagram in Bonabeau social hierarchy model with individually   different abilities
  The 1995 model of Bonabeau et al is generalized by giving each individual a different ability to win or lose a fight. We also introduce different groups such that the losers of fights between different groups are eliminated. The overall phase diagram for the first-order transition between egalitarian and hierarchical societies does not change much by these generalizations. 
Christian Schulze and Dietrich Stauffer