The monetary character of trade, use of a common medium of exchange, is shown to be an outcome of an economic general equilibrium. Monetary structure can be derived from price theory in a modified Arrow-Debreu model. Two constructs are added: transaction costs and market segmentation in trading...

Existence and efficiency of general equilibrium with commodity money is investigated in an economy where N commodities are traded at N(N-1)/2 commodity-pairwise trading posts. Trade is a resource-using activity recovering transaction costs through the spread between bid (wholesale) and ask...

This study models the bid-ask spread in financial markets as a function of asset price variability and order flow. The market-maker is characterized as passively accepting orders to buy and to sell a security at the market's prevailing price (plus or minus half the bid-ask spread). The bid-ask...