Peer Methods for the Solution of Large-Scale Differential Matrix Equations

We consider the application of implicit and linearly implicit (Rosenbrock-type) peer methods to matrix-valued ordinary differential equations. In particular the differential Riccati equation (DRE) is investigated. For the Rosenbrock-type schemes, a reformulation capable of avoiding a number of Jacobian applications is developed that, in the autonomous case, reduces the computational complexity of the algorithms. Dealing with large-scale problems, an efficient implementation based on low-rank symmetric indefinite factorizations is presented. The performance of both peer approaches up to order 4 is compared to existing implicit time integration schemes for matrix-valued differential equations.Comment: 29 pages, 2 figures (including 6 subfigures each), 3 tables, Corrected typo

Simple Utility Functions with Giffen Demand

We present some simple utility functions whose Marshallian demand functions possess the Giffen property: at some price-wealth pairs, the demand for a good marginally increases in response to an increase in its own price. The utility functions satisfy standard preference properties throughout the usual consumption set of nonnegative bundles: continuity, monotonicity, and convexity.preferences; Giffen good

A new species of the basal araneomorph spider genus Ectatosticta (Araneae, Hypochilidae) from China

The hypochilid spider Ectatosticta davidi (Simon) is redescribed on the basis of adults from Mt. Taibaishan in Shaanxi Province, China; the specimens from Qinghai Province previously identified as E. davidi by most modern authors belong to a new species described as E. deltshevi. Keywords: Araneae, Araneomorphae, Hypochilidae, Ectatosticta, Chin

A Note on Budget Balance under Interim Participation Constraints: The Case of Independent Types

We provide a simple proof of the equivalence between ex ante and ex post budget balance constraints in Bayesian mechanism design with independent types when participation decisions are made at the interim stage. The result is given an interpretation in terms of efficient allocation of risk.

Government-Mandated Discriminatory Policies

This paper provides a simple explanation for why some minority groups are economically successful, despite being subject to government-mandated discriminatory policies. We study an economy with private and public sectors in which workers invest in imperfectly observable skills that are important to the private sector but not to the public sector. A law allows native majority workers to be employed in the public sector with positive probability while excluding the minority from it. We show that even when the public sector offers the highest wage rate, it is still possible that the discriminated group is, on average, economically more successful. The reason is that the preferential policy lowers the majority's incentive to invest in imperfectly observable skills by exacerbating the informational free riding problem in the private sector labor marketDiscrimination; Informational Free Riding; Income Distribution

Optimal Provision of Multiple Excludable Public Goods

This paper studies the optimal provision mechanism for multiple excludable public goods when agents' valuations are private information. For a parametric class of problems with binary valuations, we characterize the optimal mechanism, and show that it involves bundling. Bundling alleviates the free riding problem in large economies in two ways: first, it can increase the asymptotic provision probability of socially efficient public goods from zero to one; second, it decreases the extent of use exclusions.Public Goods Provision, Bundling, Exclusion

An Efficiency Rationale for Bundling of Public Goods

This paper studies the role of bundling in the efficient provision of excludable public goods. We show that bundling in the provision of unrelated public goods can enhance social welfare. With a large number of goods and agents, first best can be approximated with pure bundling. For a parametric class of problems with binary valuations, we characterize the optimal mechanism, and show that bundling alleviates the free riding problem in large economies and decreases the extent of use exclusions. Both results are related to the idea that bundling makes it possible to reduce the incidence of exclusions because the variance in the relevant valuations decreases.Public goods provision, Bundling, Exclusion