The use of proof plans in tactic synthesis

We undertake a programme of tactic synthesis. We first formalize the notion of a tactic as a rewrite rule, then give a correctness criterion for this by means of a reflection mechanism in the constructive type theory OYSTER. We further formalize the notion of a tactic specification, given as a synthesis goal and a decidability goal. We use a proof planner. CIAM. to guide the search for inductive proofs of these, and are able to successfully synthesize several tactics in this fashion. This involves two extensions to existing methods: context-sensitive rewriting and higher-order wave rules. Further, we show that from a proof of the decidability goal one may compile to a Prolog program a pseudo- tactic which may be run to efficiently simulate the input/output behaviour of the synthetic tacti

A Rational Reconstruction and Extension of Recursion Analysis

The focus of this paper is the technique of recur8\on analysis. Recursion analysis is used by the Boyer-Moore Theorem Prover to choose an appropriate induction schema and variable to prove theorems by mathematical induction. A rational reconstruction of recursion analysis is outlined, using the technique of proof plans. This rational reconstruction suggests an extension of recursion analysis which frees the induction suggestion from the forms of recursion found in the conjecture. Preliminary results are reported of the automation of this rational reconstruction and extension using the CLAM-Oyster system

Deductive synthesis of recursive plans in linear logic

Centre for Intelligent Systems and their ApplicationsConventionally, the problem of plan formation in Artificial Intelligence deals with the generation of plans in the form of a sequence of actions. This thesis describes an approach to extending the expressiveness of plans to include conditional branches and recursion. This allows problems to be solved at a higher level, such that a single plan in such a language is capable of solving a class of problems rather than a single problem instance. A plan of fixed size may solve arbitrarily large problem instances. To form such plans, we take a deductive planning approach, in which the formation of the plan goes hand-in-hand with the construction of the proof that the plan specification is realisable. The formalism used here for specifying and reasoning with planning problems is Girard's Institutionistic Linear Logic (ILL), which is attractive for planning problems because state change can be expressed directly as linear implication, with no need for frame axioms. We extract plans by means of the relationship between proofs in ILL and programs in the style of Abramsky. We extend the ILL proof rules to account for induction over inductively defined types, thereby allowing recursive plans to be synthesised. We also adapt Abramsky's framework to partially evaluate and execute the plans in the extended language. We give a proof search algorithm tailored towards the fragment of the ILL employed (excluding induction rule selection). A system implementation, Lino, comprises modules for proof checking, automated proof search, plan extraction and partial evaluation of plans. We demonstrate the encodings and solutions in our framework of various planning domains involving recursion. We compare the capabilities of our approach with the previous approaches of Manna and Waldinger, Ghassem-Sani and Steel, and Stephen and Biundo. We claim that our approach gives a good balance between coverage of problems that can be described and the tractability of proof search

The Automation Of Proof By Mathematical Induction

Chapter appears in Handbook of Automated Reasoning Edited by: Alan Robinson and Andrei Voronkov ISBN: 978-0-444-50813-3This paper is a chapter of the Handbook of Automated Reasoning edited by Voronkov and Robinson. It describes techniques for automated reasoning in theories containing rules of mathematical induction. Firstly, inductive reasoning is defined and its importance fore reasoning about any form of repitition is stressed. Then the special search problems that arise in inductive theories are explained followed by descriptions of the heuristic methods that have been devised to solve these problems

Towards a cultural international political economy of financialisation : the transformation of private pension provision in the United Kingdom

In the last two decades especially, the scale, depth and intensity of competitive changes in the financial services marketplace have progressed to new heights. Financialisation, as it has become known, is creating new opportunities and constraints for nations, businesses and 'people', as the circuits of production have become more closely bound up with the innovative dynamics and institutions of the capital market. In an attempt to define, measure and explain the financialisation of the economy, this thesis draws upon a unique theoretical framework to explore the transformations in private pension provision. Using the work of Karl Polanyi as our guide, and particularly of those ideas found in his seminal book The Great Transformation, we posit that financialisation has gone through two different stages that we call disembedding and re-embedding. To articulate this proposition and to examine it beyond conventional economic accounts, we draw upon a wide variety of cultural (political) economic scholars, such as Veblen, Foucault, Bourdieu, Giddens, Callon and Thrift, whose ideas collectively help us to understand the cultural processes, strategies, conflicts, interactions and performances underpinning the ongoing evolution of financialisation in society. Applying this framework, we find that the collective pensions that were once part of a unified post-war political economy have come under threat from the new idea that welfare should be linked to the vagaries and anonymous circuits of the stock market. Disembedding has taken its form through the financialisation of pension provision, encouraging an explicit change from collective welfare to individual responsibility. While the individual has become precariously embedded as a financial consumer inside commercial market relations, it is doubtful whether this model is sustainable and practical as a means of delivering social inclusion and political enrichment.EThOS - Electronic Theses Online ServiceEconomic and Social Research CouncilGBUnited Kingdo

Comedy: An Annotated Bibliography of Theory and Criticism

From Plato to Umber-to Eco comedy has been a subject of perennial interest. In the 1980s there have even been two attempts, one scholarly and one fictional, to recreate the "lost" book on comedy by Plato's pupil Aristotle: by Richard Janko in Aristotle on Comedy: Towards a Reconstruction of Poetics II, which also returns us to the ancient "Tractatus Coislinianus"; and by Eco in The Name of the Rose, where murder fails to prevent disclosure of the treatise (see items 216 and 274 below). So the time seemed propitious to gather and annotate the best that has been published about comedy in a bibliography of larger scope than the one by E. H. Mikhail, Comedy and Tragedy: A Bibliography of Critical Studies (Troy: Whitston, 1972), which included only about four hundred items. This book is intended to provide a better guide through the maze of comic theory and criticism than has hitherto existed

Evaluation of the new Design Summer Year weather data using parametrical buildings

The Charted Institution of Building Services Engineers (CIBSE) updated the near extreme weather (Design Summer Year – DSY) for all 14 locations in the UK in 2016. This new release attempts to address the underlying shortcomings of the previous definition where the averaged dry bulb temperature was the sole metric to choose DSY among source weather years. The aim of this research is to evaluate whether the new definition of the probabilistic DSYs can consistently represent near extreme condition. London historical weather data and their correspondent DSYs were used in this research. Dynamic thermal modelling using EnergyPlus was carried out on large number single zone offices (parametric study) which represent a large portion of cellular offices in the UK. The predicted indoor warmth from the sample building models show that these new definitions are not always able to represent near extreme conditions. Using multiple years as DSY is able to capture different types of summer warmth but how to use one or all of these DSYs to make informed judgement on overheating is rather challenging. The recommended practice from this research is to use more warm years for the evaluation of overheating and choose the near extreme weather from the predicted indoor warmt

Age composition and survival of public housing stock in Hong Kong

Emerging notably in more developed regions, building stock ageing which is characterised by shrinking new completions and falling “mortality” has been posing challenges to various stakeholders in built environment. To find way out of this transition, we need to know how long buildings will last these days and the factors leading to their “mortality”. By using data from 1950s till to date, a comprehensive investigation is conducted to analyse the age composition and life expectancy of public housing stock in Hong Kong. What comes after are survival analysis and empirical analysis of those demolished to identify the key factors leading to demolition. Presented in this paper are the preliminary findings as well as the research agenda on the theme to model age composition and survival of both private and public building stocks in Hong Kong and other similar cities in Asia Pacific Rim such as Adelaide and Singapore, together with research activities to formulate policies for sustainable urban management