A Theory of Size and Product Diversity of Marketplaces with Application to the Trade Show Arena

Markets involve the exchange of information and products between buyers and sellers in marketplaces created by market organizers. This paper develops a theory to explain the differences in the size (number of participants) and diversity (range of products displayed) across these marketplaces. We assume that successful transactions require information transmission between parties calling for investment in time/effort. Two key factors affect this process of information interchange: diminishing marginal returns to effort encouraging diversification and congestion cost resulting from participant overload. We study a sequential model of interaction between buyers, sellers and marketplace organizers. Organizers choose the number and nature of marketplaces to organize, and set entry fees for them while buyers and sellers make participation and effort allocation decisions. We show that participants' breadth of product interest, their buying and selling intensities (i.e. how frequently they are likely to engage in future product transactions) as well as the technological innovativeness of the industry have important influences on the size and range of product diversity in the marketplace. We apply this model to the industrial trade show arena to explain differences in trade show types (horizontal with broad product focus vs. vertical with narrow product focus) across industries. Empirical tests of several propositions derived from our model provide an encouraging degree of support for our theory. Our analysis identifies several industries that appear to be underserved by one type of show or the other, suggesting possible future opportunities for organizers.

Assessing Promotion Performance of Pure Online Players: A Two-Stage Model with Sample Selection

Firms may be motivated to establish an online presence to achieve many objectives, including image-building, awareness creation, sales lead generation, or direct sales. These ends cannot be fulfilled unless customers know of and visit the firmís website. Firms with an established offline presence (mixed online players) can generate website traffic by word-of-mouth or may be reached by a consumer guessing a Web address (e.g., www.ford.com). However, pure online players must promote their websites to their targeted audience in various advertising vehicles in online and/or offline media (e.g., www.monster.com). According to Advertising Age, in 1999, the golden year for advertising-revenue-driven firms, dot-coms spent $7.4 billion in various advertising vehicles to promote their websites

Stabilizer Approximation

We propose a heuristic method to obtain the approximate groundstate for a Hamiltonian in the qubit form, based on the stabilizer formalism. These states may serve as proper initial states for further refined computation. It would be interesting to assess the efficiency and scalability of the method.Comment: 10 page