Table 1. The symbols used in the unified model.

Symbols	Description
W	The set of loci in the two-dimensional L×L lattice
A	The set of all agents (both buyers and sellers)
B	The set of buyers
S	The set of sellers
εi	The Moore neighborhood of agent i, i∈A, εi∈W
Fi	The set of friends of agent i, i∈A
Mip	The memory of agent i about locus p, i∈A, p∈W
M0	The unit memory strength of an agent about the trading locus