1,828 research outputs found

    A Physical Origin for Singular Support Conditions in Geometric Langlands Theory

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    We explain how the nilpotent singular support condition introduced into the geometric Langlands conjecture by Arinkin and Gaitsgory arises naturally from the point of view of N = 4 supersymmetric gauge theory. We define what it means in topological quantum field theory to restrict a category of boundary conditions to the full subcategory of objects compatible with a fixed choice of vacuum, both in functorial field theory and in the language of factorization algebras. For B-twisted N = 4 gauge theory with gauge group G, the moduli space of vacua is equivalent to h*/W , and the nilpotent singular support condition arises by restricting to the vacuum 0 in h*/W. We then investigate the categories obtained by restricting to points in larger strata, and conjecture that these categories are equivalent to the geometric Langlands categories with gauge symmetry broken to a Levi subgroup, and furthermore that by assembling such for the groups GL_n for all positive integers n one finds a hidden factorization structure for the geometric Langlands theory.Comment: 55 pages, 5 figures, more improvements to the expositio

    Geometric Langlands Twists of N = 4 Gauge Theory from Derived Algebraic Geometry

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    We develop techniques for describing the derived moduli spaces of solutions to the equations of motion in twists of supersymmetric gauge theories as derived algebraic stacks. We introduce a holomorphic twist of N=4 supersymmetric gauge theory and compute the derived moduli space. We then compute the moduli spaces for the Kapustin-Witten topological twists as its further twists. The resulting spaces for the A- and B-twist are closely related to the de Rham stack of the moduli space of algebraic bundles and the de Rham moduli space of flat bundles, respectively. In particular, we find the unexpected result that the moduli spaces following a topological twist need not be entirely topological, but can continue to capture subtle algebraic structures of interest for the geometric Langlands program.Comment: 55 pages; minor correction

    Explaining Classifiers using Adversarial Perturbations on the Perceptual Ball

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    We present a simple regularization of adversarial perturbations based upon the perceptual loss. While the resulting perturbations remain imperceptible to the human eye, they differ from existing adversarial perturbations in that they are semi-sparse alterations that highlight objects and regions of interest while leaving the background unaltered. As a semantically meaningful adverse perturbations, it forms a bridge between counterfactual explanations and adversarial perturbations in the space of images. We evaluate our approach on several standard explainability benchmarks, namely, weak localization, insertion deletion, and the pointing game demonstrating that perceptually regularized counterfactuals are an effective explanation for image-based classifiers.Comment: CVPR 202

    A review of Australian approaches for monitoring, assessing and reporting estuarine condition: III. Evaluation against international best practice and recommendations for the future

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    In this final component of a three-part review, we present a national synthesis and evaluation of approaches for monitoring, assessing and reporting estuarine condition across Australia. Progress is evaluated against objective criteria that together provide a model of international best practice. We critically assess the limitations, inconsistencies and gaps that are evident across Australian jurisdictions, and identify common obstacles to future progress. Major strengths and successes are also highlighted, together with specific examples of best practice from around Australia that are transferable to other States and beyond. Significant obstacles to greater national coordination of monitoring and reporting practices include inconsistent spatial scales of management, pluralistic governance structures and the lack of any overarching legislation. Nonetheless, many perceptible advances have been made over the last decade across Australia in estuarine monitoring and health assessment, and there is great potential for further progress. Finally, we provide a list of recommendations to address some of the most pressing limitations and gaps, and support improved future monitoring, assessment and reporting for Australian estuaries

    A review of Australian approaches for monitoring, assessing and reporting estuarine condition: I. International context and evaluation criteria

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    © 2016 Elsevier Ltd Given the immeasurable value of estuaries and their severe and growing pressures, sound understanding and reporting of estuarine condition is essential for their effective management and sustainable development. In light of this, we aim to provide a timely and comprehensive three-part review of the approaches currently employed for monitoring, assessing and reporting estuarine condition, focussing on Australian systems. Here, in Part 1, we establish the national and international context of our review and define globally-relevant evaluation criteria against which to assess Australian progress. We achieve this by examining effective monitoring, assessment and reporting programs from around the world and characterising ‘best practice’. We then highlight the Australian historical context and consider recent policies, frameworks, guidelines and legislation relating to the monitoring and reporting of estuarine condition nationwide

    UMS_HR_Important Information on the Families First Coronavirus Response Act Email

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    Email from Chris Lindstrom, Co-Interim CHRO, Human Resources and Tracy Elliott, Co-Interim CHRO, Human Resources to University of Maine System employees regarding the Families First Coronavirus Response Act, (FFCRA), that took effect April 1, 2020

    A manifesto for a socio-technical approach to NHS and social care IT-enabled business change - to deliver effective high quality health and social care for all

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    80% of IT projects are known to fail. Adopting a socio-technical approach will help them to succeed in the future. The socio-technical proposition is simply that any work system comprises both a social system (including the staff, their working practices, job roles, culture and goals) and a technical system (the tools and technologies that support and enable work processes). These elements together form a single system comprising interacting parts. The technical and the social elements need to be jointly designed (or redesigned) so that they are congruent and support one another in delivering a better service. Focusing on one aspect alone is likely to be sub-optimal and wastes money (Clegg, 2008). Thus projects that just focus on the IT will almost always fail to deliver the full benefits
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