1,191 research outputs found
Non-omega-overlapping TRSs are UN
This paper solves problem #79 of RTA’s list of open problems [14] — in the positive. If the
rules of a TRS do not overlap w.r.t. substitutions of infinite terms then the TRS has unique
normal forms. We solve the problem by reducing the problem to one of consistency for “similar”
constructor term rewriting systems. For this we introduce a new proof technique. We define a
relation ⇓ that is consistent by construction, and which — if transitive — would coincide with
the rewrite system’s equivalence relation =R.
We then prove the transitivity of ⇓ by coalgebraic reasoning. Any concrete proof for instances
of this relation only refers to terms of some finite coalgebra, and we then construct an equivalence
relation on that coalgebra which coincides with ⇓
Optimal Sharing Graphs for Substructural Higher-order Rewriting Systems
The notion of optimal reduction was introduced by Lévy (1980) in the context of the untyped ?-calculus, based on the concept of families of reducible expressions. It took more than a decade for an algorithm achieving this optimal reduction to be discovered, introduced by Lamping (1990) and then refined by Gonthier, Abadi & Lévy (1992). The existence of an analogous algorithm for higher-order term rewriting systems was later theorised by Van Oostrom (1996), but has of yet been unrealised.
We provide such an algorithm by defining a class of higher-order rewriting systems having Intuitionistic Linear Logic (Benton, Bierman, de Paiva & Hyland 1992) as a substitution calculus, in the sense of Van Oostrom (1994), and introduce a method of translating terms and rules into equivalent Lamping-Gonthier sharing graphs. Our system thus offers a generalisation of the mechanism for optimal reduction from second- to higher-order term rewriting systems. Moreover, in the case of match-sequential systems, we provide a specific reduction strategy, as we are able to effectively identify needed redexes.
Finally, we explore briefly the subtleties and complexities of applying the technique to various other term rewriting system, such as those with alternative substructural or polymorphic type systems, those with generalised patterns on the left-hand side, and those with rationally infinite terms. All these systems are built upon the same fundamental translation of ?-terms to sharing graphs
Towards a 100% hydrogen domestic gas network: Regulatory and commercial barriers to the first demonstrator project in the United Kingdom
Costs of zero emissions heating in new build
This report looks at the costs of delivering zero emissions heating in domestic andnon-domestic new buildings. It identifies the factors that influence these costs and how they are split between different actors, including building developers, building owners and building users over the lifetime of a technology
Sound Studies Meets Deaf Studies
Sound studies and Deaf studies may seem at first impression to operate in worlds apart. We argue in this article, however, that similar renderings of hearing, deafness, and seeing as ideal types - and as often essentialized sensory modes - make it possible to read differences between Sound studies and Deaf studies as sites of possible articulation. We direct attention to four zones of productive overlap, attending to how sound is inferred in deaf and Deaf practice, how reimagining sound in the register of low-frequency vibration can upend deafhearing dichotomies, how “deaf futurists“ champion cyborg sound, and how signing and other non-spoken communicative practices might undo phonocentric models of speech. Sound studies and Deaf studies emerge as fields with much to offer one another epistemologically, theoretically, and practically
Role of BRCA gene dysfunction in breast and ovarian cancer predisposition
Tumor suppressor genes that perform apparently generic cellular functions nonetheless cause tissue-specific syndromes in the human population when they are mutated in the germline. The two major hereditary breast/ovarian cancer predisposition genes, BRCA1 and BRCA2, appear to participate in a common pathway that is involved in the control of homologous recombination and in the maintenance of genomic integrity. How might such functions translate into the specific suppression of cancers of the breast and ovarian epithelia? Recent advances in the study of BRCA1 and BRCA2, discussed herein, have provided new opportunities to address this question
The what, why and how of aromatase inhibitors: hormonal agents for treatment and prevention of breast cancer
The third-generation aromatase inhibitors (AIs) anastrozole, exemestane and letrozole have largely replaced tamoxifen as the preferred treatment for hormone receptor – positive breast cancer in postmenopausal women. Approximately 185,000 new cases of invasive breast cancer are diagnosed yearly, and at least half of these women are both postmenopausal and eligible for adjuvant therapy with AIs. In addition, AIs are currently being tested as primary prevention therapy in large randomised trials involving tens of thousands of women at increased risk for breast cancer. Given the volume of use, internists will increasingly see postmenopausal women who are taking or considering treatment with AIs. Physicians need to be able to: (i) briefly discuss the pros and cons of using a selective estrogen receptor modulator such as tamoxifen or raloxifene vs. an AI for risk reduction and (ii) recognise and manage AI-associated adverse events. The primary purpose of this review is to help internists with these two tasks
Rockport Comprehensive Plan
This document was developed and prepared by Texas Target Communities (TxTC) at Texas A&M University
in partnership with the City of Rockport, Texas Sea Grant, Texas A&M University - Corpus Christi,
Texas A&M University - School of Law and Texas Tech University.Founded in 1871, the City of Rockport aims to continue growing economically and sustainably. Rockport is a resilient community dedicated to sustainable growth and attracting businesses to the area. Rockport is a charming town that offers a close-knit community feel and is a popular tourist destination for marine recreation, fairs, and exhibitions throughout the year. The Comprehensive Plan 2020-2040 is designed to guide the city of Rockport for its future growth. The guiding principles for this planning process were Rockport's vision statement and its corresponding goals, which were crafted by the task force. The goals focus on factors of growth and development including public participation, development considerations, transportation, community facilities, economic development, parks, and housing and social vulnerability
Dysregulation of neuronal iron homeostasis as an alternative unifying effect of mutations causing familial Alzheimer's disease
The overwhelming majority of dominant mutations causing early onset familial Alzheimer's disease (EOfAD) occur in only three genes, PSEN1, PSEN2, and APP. An effect-in-common of these mutations is alteration of production of the APP-derived peptide, amyloid ß (Aß). It is this key fact that underlies the authority of the Amyloid Hypothesis that has informed Alzheimer's disease research for over two decades. Any challenge to this authority must offer an alternative explanation for the relationship between the PSEN genes and APP. In this paper, we explore one possible alternative relationship - the dysregulation of cellular iron homeostasis as a common effect of EOfAD mutations in these genes. This idea is attractive since it provides clear connections between EOfAD mutations and major characteristics of Alzheimer's disease such as dysfunctional mitochondria, vascular risk factors/hypoxia, energy metabolism, and inflammation. We combine our ideas with observations by others to describe a "Stress Threshold Change of State" model of Alzheimer's disease that may begin to explain the existence of both EOfAD and late onset sporadic (LOsAD) forms of the disease. Directing research to investigate the role of dysregulation of iron homeostasis in EOfAD may be a profitable way forward in our struggle to understand this form of dementia
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