Mutual raiding of production and the emergence of exchange

Joint exchange and raiding can emerge in a world of mutual raiding when the appropriated production is less valuable to the appropriator than to the defender and the defense is not too inferior to attack. The amounts of resources allocated to production and raiding and the amounts of goods exchanged reciprocally are determined endogenously. The model reduces to pure exchange and pure raiding as special cases. Pure exchange emerges when the usability of appropriation is sufficiently low. Pure raiding emerges if the defense is sufficiently inferior to attack. The results of the model are intermediate between the results of the two extreme cases.