Envelopes, indicators and conservativeness

A well known theorem proved (independently) by J. Paris and H. Friedman states that BΣn +1 (the fragment of Arithmetic given by the collection scheme restricted to Σn +1‐formulas) is a Πn +2‐conservative extension of IΣn (the fragment given by the induction scheme restricted to Σn ‐formulas). In this paper, as a continuation of our previous work on collection schemes for Δn +1(T )‐formulas (see [4]), we study a general version of this theorem and characterize theories T such that T + BΣn +1 is a Πn +2‐conservative extension of T . We prove that this conservativeness property is equivalent to a model‐theoretic property relating Πn ‐envelopes and Πn ‐indicators for T . The analysis of Σn +1‐collection we develop here is also applied to Σn +1‐induction using Parsons' conservativeness theorem instead of Friedman‐Paris' theorem. As a corollary, our work provides new model‐theoretic proofs of two theorems of R. Kaye, J. Paris and C. Dimitracopoulos (see [8]): BΣn +1 and IΣn +1 are Σn +3‐conservative extensions of their parameter free versions, BΣ–n +1 and IΣ–n +1.Junta de Andalucía TIC-13

Induction, minimization and collection for Δ n+1 (T)–formulas

For a theory T, we study relationships among IΔ n +1 (T), LΔ n+1 (T) and B * Δ n+1 (T). These theories are obtained restricting the schemes of induction, minimization and (a version of) collection to Δ n+1 (T) formulas. We obtain conditions on T (T is an extension of B * Δ n+1 (T) or Δ n+1 (T) is closed (in T) under bounded quantification) under which IΔ n+1 (T) and LΔ n+1 (T) are equivalent. These conditions depend on Th Πn +2 (T), the Π n+2 –consequences of T. The first condition is connected with descriptions of Th Πn +2 (T) as IΣ n plus a class of nondecreasing total Π n –functions, and the second one is related with the equivalence between Δ n+1 (T)–formulas and bounded formulas (of a language extending the language of Arithmetic). This last property is closely tied to a general version of a well known theorem of R. Parikh. Using what we call Π n –envelopes we give uniform descriptions of the previous classes of nondecreasing total Π n –functions. Π n –envelopes are a generalization of envelopes (see [10]) and are closely related to indicators (see [12]). Finally, we study the hierarchy of theories IΔ n+1 (IΣ m ), m≥n, and prove a hierarchy theorem.Ministerio de Educación y Cultura DGES PB96-134

THREE ESSAYS ON THE LINKS BETWEEN LOCAL GOVERNMENT STRUCTURAL CHANGES AND PUBLIC FINANCE

This dissertation, comprised of three essays, explains and evaluates local government structural changes from a public finance perspective. The first essay examines the determinants of the rapid growth of special districts, while the next two essays estimate the effects on property values of school district consolidation and village dissolution in New York State, respectively. Together, the three essays contribute to our understanding of the causes and consequences of local government structural changes in the United States. By bring together two central trends in state and local public finance, namely, the expansion of state-imposed tax and expenditure limitations (TELs) and the rapid growth of special districts, the first essay looks into the hypothesis that TELs are partly responsible for the increase of special districts over the last several decades. To eliminate the possible omitted variable bias, I employ a combination of fixed effects, regional time trends and approximate measures of fiscal conservativeness. Based on a national data set of counties over the period 1972-2007, I find TELs, on average, increase the use of special districts (circumvention effects), whereas TELs don’t force local governments to cut their intergovernmental fiscal transfer to special districts in the same county area (deterrent effects). The estimation results are robust to multiple tests of common trends assumptions, five alternative measures of TELs, alternative model specifications and different empirical strategies. This results confirm the theory that special districts have been extensively created by local general-purpose governments as an institutional strategy to circumvent the fiscal constraints imposed by TELs. The second essay explores the impacts of school district consolidation on property values in upstate New York from 2000 to 2012. This research, conducted in collaboration with Professors William Duncombe and John Yinger, adds a time dimension to research on the property-value impacts of consolidation. By combining propensity score matching and double-sales data to compare house value changes in consolidating and comparable school districts, we find that it takes time either for the advantages of consolidation to be apparent to homebuyers or for the people who prefer consolidated districts to move in. In addition, the long-run impacts of consolidation on house values are positive in low-income census tracts but negative in high-income census tracts. This result suggests that high-income households are particularly attached to the benefits, such as close contact with teachers, of small districts. Streams of institutional, economic and fiscal factors recently have been converging and substantially changing the landscape of local government in the United States. Dissolution, an old and new approach, has increasingly been used and therefore drawn much public attention nowadays. The third essay provides the first study investigating whether village dissolution, as a form of general-purpose government reorganization, affects the attractiveness of local communities. In New York, voters in several villages voted to dissolve the village and hence to shift all government services to the town government in which the village is located. I show that village dissolution does not alter the amount people are willing to pay inside the (eliminated) village boundaries, but that the price of housing declines in areas of the town outside the village (TOV). Presumably, residents in the TOV areas are upset with the negative externalities of village dissolution

The role of admission control in assuring multiple services quality

Considering that network overprovisioning by itself is not always an attainable and everlasting solution, Admission Control (AC) mechanisms are recommended to keep network load controlled and assure the required service quality levels. This article debates the role of AC in multiservice IP networks, providing an overview and discussion of current and representative AC approaches, highlighting their main characteristics, pros and cons regarding the management of network services quality. In this debate, particular emphasis is given to an enhanced monitoring-based AC proposal for assuring multiple service levels in multiclass networks.Centro de Ciências e Tecnologias da Computação do Departamento de Informática da Universidade do Minho (CCTC

Almost Similar Tests for Mediation Effects and other Hypotheses with Singularities

Testing for mediation effects is empirically important and theoretically interesting. It is important in psychology, medicine, economics, accountancy, and marketing for instance, generating over 90,000 citations to a single key paper in the field. It also leads to a statistically interesting and long-standing problem that this paper solves. The no-mediation hypothesis, expressed as $H_{0}:\theta_{1}\theta_{2}=0$, defines a manifold that is non-regular in the origin where rejection probabilities of standard tests are extremely low. We propose a general method for obtaining near similar tests using a flexible $g$-function to bound the critical region. We prove that no similar test exists for mediation, but using our new varying $g$-method obtain a test that is all but similar and easy to use in practice. We derive tight upper bounds to similar and nonsimilar power envelopes and derive an optimal test. We extend the test to higher dimensions and illustrate the results in a trade union sentiment application

A Call to Cities: Run Out of Water or Create Resilience and Abundance?

New management choices, with new approaches to urbanization and integrated water-energy-food management, are emerging as critical to combat water stress. Urban strategies and tactics are explored in this chapter with a focus on scaling effective solutions and approaches. This includes a focus on small, modular, and integrated water-energy-food hubs; off-grid and localized “circular economy” services that are affordable, accessible, and reliable; blended finance for new technologies, infrastructure and business models, strategic plans, and policies; and urban, behavioral, and decision sciences-informed decisions and new public-private-research-driven partnerships and processes. There are two key messages: first, business as usual could lead to “running out” of water where it’s needed most—in cities and for agricultural and industrial production. Second, “innovators” and “early adopters” of market-based and data-driven efforts can help scale solutions led by people and communities investing in new ways to integrate urban water, energy, and food systems. The chapter concludes with discussion on a new, proactive “maturity” model, enabling integrated urban infrastructure systems, governance, and cross-sector innovation. This includes market-based and data-driven responses that first focus on improving quality of life, sustainability, and resilience of communities, bringing valued services via water-energy-food nexus decisions

Adapting to change: Time for climate resilience and a new adaptation strategy. EPC Issue Paper 5 March 2020

The dramatic effects of climate change are being felt across the European continent and the world. Considering how sluggish and unsuccessful the world has been in reducing greenhouse gas (GHG) emissions, the impacts will become long-lasting scars. Even implementing radical climate mitigation now would be insufficient in addressing the economic, societal and environmental implications of climate change, which are expected to only intensify in the years to come. This means climate mitigation must go hand in hand with the adaptation efforts recognised in the Paris Agreement. And although the damages of climate change are usually localised and adaptation measures often depend on local specificities, given the interconnections between ecosystems, people and economies in a globalised world there are strong reasons for European Union (EU) member states to join forces, pool risk and cooperate across borders. Sharing information, good practices, experiences and resources to strengthen resilience and enhance adaptive capacity makes sense economically, environmentally and socially. The European Commission’s 2013 Adaptation Strategy is the first attempt to set EU-wide adaptation and climate resilience and could be considered novel in that it tried to mainstream adaptation goals into relevant legislation, instruments and funds. It was not very proactive, however. It also lacked long-term perspective, failed to put the adaptation file high on the political agenda, was under resourced, and suffered from knowledge gaps and silo thinking. The Commission’s European Green Deal proposal, which has been presented as a major step forward to the goal of Europe becoming the world’s first climate-neutral continent, suggests that the Commission will adopt a new EU strategy on adaptation to climate within the first two years of its mandate (2020-2021). In light of the risks climate change poses to ecosystems, societies and the economy (through inter alia the vulnerability of the supply chain to climate change and its potential failure to provide services to consumers), adaptation should take a prominent role alongside mitigation in the EU’s political climate agenda. Respecting the division of treaty competences, there are important areas where EU-wide action and support could foster the continent’s resilience to climate change. The European Policy Centre (EPC) project “Building a climate-resilient Europe”, which has culminated in this Issue Paper, has identified the following: (i) the ability to convert science-based knowledge into preventive action and responsible behaviour, thus filling the information gap; (ii) the need to close the protection gap through better risk management and risk sharing; (iii) the necessity to adopt nature-based infrastructural solutions widely and tackle the grey infrastructure bias; and (iv) the need to address the funding and investment gap. This Issue Paper aims to help inform the upcoming EU Adaptation Strategy and, by extension, strengthen the EU’s resilience to climate change. To that end, the authors make a call for the EU to mainstream adaptation and shift its focus from reacting to disasters to a more proactive approach that prioritises prevention, risk reduction and resilience building. In doing so, the EU must ensure fairness and distributive justice while striving for climate change mitigation and protecting the environment and biodiversity. To succeed, the new EU Adaptation Strategy will need to address specific challenges related to the information, protection, funding and investment gaps; and the grey infrastructure bias. To tackle and address those challenges, this Paper proposes 17 solutions outlined in Table 1 (see page 6)