Castelnuovo-Mumford Regularity in Biprojective Spaces

We define the concept of regularity for bigraded modules and bigraded polynomial ring. In this setting we prove analogs of some of the classical results on $m$-regularity for graded modules over polynomial algebras.Comment: 17 Pages, 2 figure

Slotting Allowances and Retailer Market Power

This paper uses a bilateral oligopoly model to study the slotting allowances in retailing industries. There are two symmetric manufacturers competing in the upstream market. In the downstream, there are a large retailer with considerable market share, and many small retailers with insignificant market shares. Suppose that only the large retailer is able to require slotting allowances. The retailers engage in price competition with spatial differentiation. The model suggests that the large retailer uses slotting allowances to capitalize its market power. By requiring slotting fees, the large retailer can raise the wholesale prices faced by the competing small retailers, and therefore lower their profit margins and market shares. The large retailer, on the contrary, achieves greater profit margins and market share. The lump sum part of the slotting fees is wholly bore by the manufacturers. But the slotting fees that are linear to the sales are actually bore by the competing small retailers and their customers. In this sense, requiring slotting allowance is an exclusionary strategy of the large retailer.Exclusionary strategy, Market power, Slotting allowance

Discount Store

A retail store can profitably commit to the lowest prices because that allows it to take significantly greater market share. If a discount store acquires a competing convenience store, the average retail price tends to go up. When the upstream market is oligopolistic, the discounter can exert buyer power in the upstream market and thus earn even more profits. That also allows the discounter to lower its competitors' profit margins and sales. The average retail price goes down because the buyer power leads to more sales through the discounter. However, the consumers as a whole may not better off, and the social welfare decreases.Buyer power, Channel fees, Countervailing power, Discount store