RECURSIVE ALGORITHMS FOR THE ELIMINATION OF REDUNDANT PATHS IN SPATIAL LAG OPERATORS*

ABSTRACT. Recursive algorithms for the elimination of redundant paths in spatial lag operators are introduced. It is shown that these algorithms have superior computational properties in comparison with the cumbersome procedure proposed by Ross and Harary (1952). A rigorous definition of spatial lag operators is given, while a number of mathematical results and properties are derived. Theoretical and empirical results regarding the performance of the proposed algorithms are presented.     

Shopping,social inclusion and the urban geographies of people with intellectual disability

In this paper, we examine the social geographies of people with intellectual disabilities. We focus particular attention on the significance of shopping and spaces of consumption as they relate to questions social inclusion and belonging in the lives of PWID. The focus on consumption offers a useful counterpoint to a prevailing policy emphasis on social inclusion through productive activities. The paper also contributes to the literature on intellectual disability within social and health geography, shedding light on the varied socio-spatial experiences of people beyond the confines of community-care facilities and other separate spaces. Our analysis draws on data collected from a participatory research project in Toronto (Canada). The project involved a small but diverse group of people with intellectual disabilities, who led academic researchers on a series of excursions designed to explore those places and routes that make up their everyday social geographies. Shopping emerged as a significant but often ambivalent theme in the context of these geographies, and the analysis demonstrates the complex interplay of autonomy and control, pleasure and restraint, care and support that shape people’s experiences of consumption. We conclude by discussing the significance of these findings for notions of social inclusion and belonging.     

Humans in the Environment: Plants,Animals and Landscapes in Mesolithic Britain and Ireland

Environmental archaeology has historically been central to Mesolithic studies in Britain and Ireland. Whilst processual archaeology was concerned with the economic significance of the environment, post-processual archaeology later rejected economically driven narratives, resulting in a turn away from plant and animal remains. Post-processual narratives focused instead on enigmatic ‘ritual’ items that economic accounts struggled to suitably explain. Processual accounts of landscapes, grounded in economic determinism, were also rejected in favour of explorations of their sociocultural aspects. However, in moving away from plant and animal remains, such accounts lacked the ability to rigorously explore the specificities of particular landscapes and humans actions within them. This paper will bridge this gap by considering how palaeoecological and zooarchaeological analyses can be used to explore human interactions with plants and animals, which were key in developing understandings and relationships that ultimately structured landscapes, influenced past human actions and shaped archaeological assemblages.     

Envisioning Future Landscapes in the Environmentally Sensitive Areas of Scotland

Environmentally Sensitive Areas (ESAs) designated under EC Structure Regulation 797/85 now cover 1.4 million ha of the Scottish countryside and are likely to make a substantial contribution to the regulation of landscape change. Visual changes to landscapes with (policy on) and without (policy off) the ESA programme in two Scottish ESA areas, Breadalbane and the Machair, are predicted through impact-assessment procedures and computer manipulation of photographic images. The methodological requirements for such predictions are outlined and substantial differences in landscape characteristics under policy on/off scenarios are revealed. Such approaches to landscape change are an essential foundation for the development of environmental cost-benefit analyses and will contribute to public consultation processes.