Deformations of the discrete Heisenberg group

We study deformations of the discrete Heisenberg group acting properly discontinuously on the Heisenberg group from the left and right and obtain a complete description of the deformation space.Comment: 8 page

A method of deforming G-structures

We consider deformations of G-structures via the right action on the frame bundle in a base-point-dependent manner. We investigate which of these deformations again lead to G-structures and in which cases the original and the deformed G-structures define the same instantons. Further, we construct a bijection from connections compatible with the original G-structure to those compatible with the deformed G-structure and investigate the change of intrinsic torsion under the aforementioned deformations. Finally, we consider several examples.Comment: 14 pages; v3: references added, published in Journal of Geometry and Physic

U.S. Domestic Airline Pricing, 1995-2004

Between 1995 and 2004, I find that airline prices fell more than 20% adjusted for inflation. I also show that premia at hub airports declined and that there is now substantially less disparity between the cheaper and more expensive airports than there was a decade ago. Still, I find that prices remain quite high at a few dominated airports.Airline Competition, Airline Hubs, Price Indices

Markets for Anthropogenic Carbon Within the Larger Carbon Cycle

Human activity has disrupted the natural balance of greenhouse gases in the atmosphere and is causing climate change. Burning fossil fuels and deforestation result directly in about 9 gigatons of carbon (GtC) emissions per year against the backdrop of the natural carbon flux — emission and uptake — of about 210 GtC per year to and from oceans, vegetation, soils and the atmosphere. But scientific research now indicates that humans are also impacting the natural carbon cycle through less-direct, but very important, mechanisms that are more difficult to monitor and control. I explore the challenges this presents to market or regulatory mechanisms that might be used to reduce greenhouse gases: scientific uncertainty about these indirect processes, pricing heterogeneous impacts of similar human behaviors, and the difficulty of assigning property rights to a far larger set of activities than has previously been contemplated. While this does not undermine arguments for market mechanisms to control direct anthropogenic release of greenhouse gases, it suggests that more research is needed to determine how and whether these mechanisms can be extended to address indirect human impacts.

The Trouble With Electricity Markets (and some solutions)

Since June 2000, California's electricity market has produced extremely high prices and threats of supply shortages. But California's is only the most recent and visible example of the trouble with deregulated wholesale electricity markets. In this paper, Borenstein argues that the difficulties that have appeared in California and elsewhere are intrinsic to the design of current electricity markets, in which demand exhibits virtually no price responsiveness and supply faces strict production constraints. Such a structure will necessarily lead to periods of shortage and of surplus, which will be accompanied by great volatility in prices and profits. This result, however, is not inevitable. By encouraging price-responsive demand and long-term wholesale contracts for electricity, policy makers can create electricity markets that will function much more smoothly.Regulatory Reform

Neural Networks and their application in the fields of corporate finance

This article deals with the usefulness of neuronal networks in the area of corporate finance. Firstly, we highlight the initial applications of neural networks. One can distinguish two main types: layer networks and self organizing maps. As Altman al. (1994) underlined, the use of layer networks has improved the reclassifying rate in models of bankruptcy forecasting. These first applications improved bankruptcy forecasting by showing a relationship between capital structure and corporate performance. The results highlighted in our second part, show the pertinence of the use of the algorithm of Kohonen applied to qualitative variables (KACM). More particularly, in line with Altman (1968, 1984), one can suggest the coexistence of negative and positive effects of financial structure on performance. This result allows us to question scoring models and to conclude as to a non-linear relationship. In a larger framework, the methodology of Kohonen has allowed a better perception of the factors able to explain the leasing financing (Cottrell et al., 1996). The objective is here to explain the factors of the choice between leasing and banking loans. By using different variables, we highlight the characteristics of firms which most often use leasing. The corporate financing policy could be explained by: the cost of the financing, advantages of leasing or by the minimization of agency costs in leasing, we highlight a relationship between resorting to leasing and credit rationing.neural netwoks, SOM, corporate finance

U.S. Domestic Airline Pricing, 1995-2004

Between 1995 and 2004, I find that airline prices fell more than 20% adjusted for inflation. I also show that premia at hub airports declined and that there is now substantially less disparity between the cheaper and more expensive airports than there was a decade ago. Still, I find that prices remain quite high at a few dominated airports.Airline Competition, Airline Hubs, Price Indices

Wealth Transfers from Implementing Real-Time Retail Electricity Pricing

Adoption of real-time electricity pricing %u2014 retail prices that vary hourly to reflect changing wholesale prices %u2014 removes existing cross-subsidies to those customers that consume disproportionately more when wholesale prices are highest. If their losses are substantial, these customers are likely to oppose RTP initiatives unless there is a supplemental program to offset their loss. Using data on a random sample of 636 industrial and commercial customers in southern California, I show that RTP adoption would result in significant transfers compared to a flat-rate tariff. When compared to the time-of-use rates (simple peak/offpeak tariffs) that these customers already face, however, the transfers drop by nearly half; even under the more extreme price volatility scenario that I examine, 90% of customers would see changes of between a 9% bill reduction and a 14% bill increase. Though customer price responsiveness reduces the loss incurred by those with high-cost demand profiles, I also demonstrate that this offsetting effect is unlikely to be large enough for most customers with costly demand patterns to completely offset their lost cross-subsidy. The analysis suggests that adoption of real-time pricing may be difficult without a supplemental program that compensates the customers who are made worse off by the change. I discuss how "two-part RTP" programs, which allow customers to purchase a baseline quantity at regulated TOU rates, can reduce the transfers associated with adoption of RTP.

Customer Risk from Real-Time Retail Electricity Pricing: Bill Volatility and Hedgability

One of the most critical concerns that customers have voiced in the debate over real-time retail electricity pricing is that they would be exposed to risk from fluctuations in their electricity cost. The concern seems to be that a customer could find itself consuming a large quantity of power on the day that prices skyrocket and thus receive a monthly bill far larger than it had budgeted for. I analyze the magnitude of this risk, using demand data from 1142 large industrial customers, and then ask how much of this risk can be eliminated through various straightforward financial instruments. I find that very simple hedging strategies can eliminate more than 80% of the bill volatility that would otherwise occur. Far from being complex, mystifying financial instruments that only a Wall Street analyst could love, these are simple forward power purchase contracts, and are already offered to retail customers by a number of fully-regulated utilities that operate real-time pricing programs. I then show that a slightly more sophisticated application of these forward power purchases can significantly enhance their effect on reducing bill volatility.