14,029 research outputs found

    Convergence between Categorical Representations of Reeb Space and Mapper

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    The Reeb space, which generalizes the notion of a Reeb graph, is one of the few tools in topological data analysis and visualization suitable for the study of multivariate scientific datasets. First introduced by Edelsbrunner et al., it compresses the components of the level sets of a multivariate mapping and obtains a summary representation of their relationships. A related construction called mapper, and a special case of the mapper construction called the Joint Contour Net have been shown to be effective in visual analytics. Mapper and JCN are intuitively regarded as discrete approximations of the Reeb space, however without formal proofs or approximation guarantees. An open question has been proposed by Dey et al. as to whether the mapper construction converges to the Reeb space in the limit. In this paper, we are interested in developing the theoretical understanding of the relationship between the Reeb space and its discrete approximations to support its use in practical data analysis. Using tools from category theory, we formally prove the convergence between the Reeb space and mapper in terms of an interleaving distance between their categorical representations. Given a sequence of refined discretizations, we prove that these approximations converge to the Reeb space in the interleaving distance; this also helps to quantify the approximation quality of the discretization at a fixed resolution

    Agricultural and Small Business Retirement Plans and Needs for Information: Evidence from a Vermont Survey

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    A survey of Vermont agricultural and small business owners and managers was conducted to examine their retirement plans and needs for information. Results from 828 respondents indicate that 42% of them do not have any retirement plan and 45% of the surveyed businesses do not offer any retirement plan for their employees. Results also suggest that most small business owners and managers who do not have a retirement plan are not very interested in more information on retirement planning.Consumer/Household Economics,
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