This is a short proof of the existence of finite sets of edges in graphs with more than one end, such that after removing them we obtain two components which are nested with all their isomorphic images. This was first done in “Cutting up graphs” [4]. Together with a certain tree construction and some elementary Bass–Serre theory this yields a combinatorial proof of Stallings’ theorem on the str...

More general results, including arbitrary Fuchsian groups, can be found in the paper [Bo2] of Borcherds, Sect. 7. Most of them have been proved by the Selberg trace formula, see [Iv] and also [Fi]. The Selberg trace formula in its standard form causes the restriction that the weight is > 2. Borcherds mentions that “with a bit more care this also works for weight 2”. As we mentioned, this bit mo...

This paper presents new estimates of annual U.S. production of pig iron dating back to 1827. These estimates are used to assess the vulnerability of the antebellum iron industry to foreign competition and the role of the tariff in fostering the industry’s early development. Domestic pig iron production is found to be highly sensitive to changes in import prices. Although import price fluctuatio...

a r t i c l e i n f o We explore aspects of two-part tariff competition between duopolists providing a homogeneous service when consumers differ with respect to their usage levels. Competition in only one price component (the fee or the rate) may allow both firms to enjoy positive profits if the other price component has been set at levels different enough between firms. Fixing one price compon...

The rapid diffusion of more channels for shopping posits new challenges for retailers, who need to compete in a complex environment for avoiding the problem of consumer cross-channel free riding. To discourage this behaviour, we propose a new environment where one retailer simultaneously handles more channels. The emerging integrated environment would engage more consumers if compared to the si...

This article aims at identifying the macroeconomic indicators that account for the Argentine financial crisis. For this purpose, an early warning system (EWS) is built based on a probit model that incorporates six monthly variables spanning the time period between February 1991 and February 2000. The results indicate that the significant indicators are the consumer price index and the ratio of ...

Several studies suggest that the temperature of the inner canthus of the eye (T(ca)), determined with infrared thermal imaging, is an appropriate method for core temperature estimation in mass screening of fever. However, these studies used the error prone tympanic temperature as a reference. Therefore, we compared T(ca) to oesophageal temperature (T(es)) as gold standard in 10 subjects during ...

The poster addresses Photonic Services as a general approach to endto-end connection over optical networks and possible types of applications that can benefit from them. Features and known challenges are highlighted. Also expected fields of application are listed and precise time transfer together with atomic clock comparison is discussed in detail with specific results.

Although price-matching refund policies are common in many retail environments, the impact of such policies on consumers has largely been ignored. This article reports the results of three studies that examine price-matching policies from a consumer perspective. Study 1 shows that consumers perceive price-matching policies as signals of low store prices and that the presence of a refund increas...

This paper explains a technique and presents empirical results for measuring the change in elderly consumer’s welfare due to price changes in items in the Consumer Price Index (CPI). A new approach for measuring welfare changes due to price changes in owner-occupied housing in a static and dynamic setting is the cornerstone of this research. The model treats housing as an asset with the fundame...