We obtain several combinatorial results about chains, cycles and orbits of the elements of the symmetric inverse semigroup ISn and the set Tn of nilpotent elements in ISn. We also get some estimates for the growth of |ISn| and |Tn|, and study random products of elements from ISn.

The differences between ECNs and Nasdaq market makers are used to formulate and test several hypotheses about the choice of trading venue and the importance of ECN trades in the price discovery process. Trades are more likely to occur on ECNs when spreads are narrow and when trading volume and stock-return volatility are high. Medium and large trades on ECNs have lower effective spreads than co...

We provide experimental evidence that contractual incompleteness, i.e., the absence of third party enforcement of workers’ effort or the quality of the good traded, causes a fundamental change in the nature of market interactions. If contracts are complete the vast majority of trades are initiated by public offers. Most trades take place in one-shot transactions and the contracting parties are ...