Truthful approximation mechanisms for restricted combinatorial auctions

When attempting to design a truthful mechanism for a computationally hard problem such as combinatorial auctions, one is faced with the problem that most efficiently computable heuristics can not be embedded in any truthful mechanism (e.g. VCG-like payment rules will not ensure truthfulness).We develop a set of techniques that allow constructing efficiently computable truthful mechanisms for combinatorial auctions in the special case where each bidder desires a specific known subset of items and only the valuation is unknown by the mechanism (the single parameter case). For this case we extend the work of Lehmann, O'Callaghan, and Shoham, who presented greedy heuristics. We show how to use If-Then-Else constructs, perform a partial search, and use the LP relaxation. We apply these techniques for several canonical types of combinatorial auctions, obtaining truthful mechanisms with provable approximation ratios.     

The founder's dilemma

Why do people start businesses? For the money and the chance to control their own companies, certainly. But new research from Harvard Business School professor Wasserman shows that those goals are largely incompatible. The author's studies indicate that a founder who gives up more equity to attract cofounders, new hires, and investors builds a more valuable company than one who parts with less equity. More often than not, however, those superior returns come from replacing the founder with a professional CEO more experienced with the needs of a growing company. This fundamental tension requires founders to make "rich" versus "king" trade-offs to maximize either their wealth or their control over the company. Founders seeking to remain in control (as John Gabbert of the furniture retailer Room & Board has done) would do well to restrict themselves to businesses where large amounts of capital aren't required and where they already have the skills and contacts they need. They may also want to wait until late in their careers, after they have developed broader management skills, before setting up shop. Entrepreneurs who focus on wealth, such as Jim Triandiflou, who founded Ockham Technologies, can make the leap sooner because they won't mind taking money from investors or depending on executives to manage their ventures. Such founders will often bring in new CEOs themselves and be more likely to work with their boards to develop new, post-succession roles for themselves. Choosing between money and power allows entrepreneurs to come to grips with what success means to them. Founders who want to manage empires will not believe they are successes if they lose control, even if they end up rich. Conversely, founders who understand that their goal is to amass wealth will not view themselves as failures when they step down from the top job.     

Voluntary disclosures and information production by analysts

We analyze the voluntary disclosure decision of a manager when analysts scrutinize the quality of disclosure. We derive an equilibrium in which managers voluntarily disclose unfavorable information only if sufficiently precise, but disclose favorable news with lower levels of accuracy. We show that analysts cover good news disclosures with higher scrutiny. To the extent analysts rely on mandatory financial reports to interpret voluntary disclosures, we show that more precise financial reports may lead to more precise but less frequent voluntary disclosures. Moreover, a slant toward conservatism in financial reports can lead to less precise yet more frequent voluntary disclosures.     

Two-stage elimination contests with optimal head starts

We study two-stage elimination Tullock contests. In the first stage all the players compete against each other; then some advance to the second stage while the others are removed. The finalists compete against each other in the second stage, and one of them wins the prize. To maximize the expected total effort, the designer can give a head start to the winner of the first stage when he competes against the other finalists in the second stage. We show that the optimal head start, independent of the number of finalists, always increases the players’ expected total effort. We also show how the number of players and finalists affect the value of the optimal head start.     

A transitions model for sustainable mobility

This paper reports on the development of a model for assessing transitions to sustainable mobility. The model uses the concepts of transition theory as a framework for assessing possible pathways by which a transition to a sustainable mobility society might happen. The modelling approach combines agent-based modelling techniques with a system dynamics structure. It is original in that there are two levels of agent. There are a small number of complex agents, which have an internal structure and are therefore subsystems within society, and a larger number of simple agents. Based on the UK data, the results show that Hydrogen Fuel Cell Vehicles (FCVs) come to dominate, but only in the very long run (after 2030), while biofuels and ICE (Internal Combustion Engine)-electric hybrids are the main alternatives to the regime in the next 10–30 years, because a) they are already developed and b) they fit better into current infrastructures. The model shows that technological transitions are most likely. Lifestyle change transitions require sustained pressure from the environment on society and behavioural change from consumers.     

Corporate fraud and investment distortions in efficient capital markets

Inefficient investment allocation induced by corporate fraud, where informed insiders strategically manipulate outside investors' beliefs, has been endemic historically and has recently attracted much attention. We reconcile corporate fraud and investment distortions with efficient capital markets, building on shareholder‐manager agency conflicts and investment renegotiation in active takeover markets. Because investments that are ex post inefficient are not renegotiation proof, the optimal renegotiation‐proof contract induces overstatements by managers, accompanied by overinvestment in low return states and underinvestment in high return states by rational investors. Our framework also helps explain why easy access to external capital appears to facilitate corporate fraud.     

Strategic information sharing between competing retailers in a supply chain with endogenous wholesale price

This paper introduces a new motivation for information sharing in decentralized supply chains—as a mechanism to achieve truthful information sharing and to reduce signaling costs. We study a two-echelon supply chain with one manufacturer selling a homogenous product to n price-setting competing retailers. Each retailer has access to private information about the potential market demand, and the retailers have an ex-ante incentive to share this information with each other and to conceal the information from the manufacturer. However, without a mechanism that induces the retailers to truthful information exchange as their strategic choice, no information can be exchanged via pure communication (cheap talk). To overcome this obstacle, two signaling games are analyzed: in the first game, information is shared truthfully among the retailers; in the second game, information is also shared truthfully with the manufacturer. We show that under some conditions sharing information with the manufacturer results in a higher profit for the retailers.     

The WTO deal on basic telecommunications : Big bang or little whimper?

It has been widely asserted that the Group on Basic Telecommunications (GBT) agreement reached in February 1997 is a significant step forward for the cause of global telecommunications liberalization. This article brings together two authors on different sides of the needed debate about the potential impact of the GBT deal. Following a brief introduction, William Drake argues that the GBT deal could, depending on its implementation, have a substantial liberalizing effect not only on specific markets, but also on the broader institutional arrangements of the global telecommunications policy environment. In response, Eli Noam argues that the GBT is useful, but that its significance is being greatly exaggerated, that most policy changes were taking place anyway, and that it could in some cases have the negative effect of slowing down the process of global liberalization.     

Combinatorial auctions with decreasing marginal utilities

In most of microeconomic theory, consumers are assumed to exhibit decreasing marginal utilities. This paper considers combinatorial auctions among such submodular buyers. The valuations of such buyers are placed within a hierarchy of valuations that exhibit no complementarities, a hierarchy that includes also OR and XOR combinations of singleton valuations, and valuations satisfying the gross substitutes property. Those last valuations are shown to form a zero-measure subset of the submodular valuations that have positive measure. While we show that the allocation problem among submodular valuations is NP-hard, we present an efficient greedy 2-approximation algorithm for this case and generalize it to the case of limited complementarities. No such approximation algorithm exists in a setting allowing for arbitrary complementarities. Some results about strategic aspects of combinatorial auctions among players with decreasing marginal utilities are also presented.     

Approaches in political science to the study of development

It is the argument of this paper that the over‐rigidified trajectories of the diverse conceptual and institutional frameworks that have evolved both internationally and locally over time, and have been varyingly informed by dominant interests, intent, ideology, and fashion, have been dysfunctional to scholarships. While appropriately multidisciplinary in character, moreover, development studies nevertheless is on occasion not the most appropriate framework in which to consider problems and issues that may call for more sharply focused specializations. The plea is accordingly one for pragmatic disciplinary, institutional and paradigmatic flexibility that will enable the successful and creative addressal of contemporary challenges.