Synthetic aperture radar (SAR) images are inherently degraded by multiplicative speckle noise where thresholdingbased methods in the transform domain are appropriate. Being sparse, the coefficients in the transformed domain play a key role in the performance of any thresholding methods. It has been shown that the coefficients of nonsubsampled shearlet transform (NSST) are sparser than those of ...

With the standard fibre being a coset manifold, the transformation of a connection form in a fibre bundle under the action of the isometry group includes a dependence on the fibre coordinate. Elimination of the fibre coordinate from the transformation rule implies that the standard fibre is a Lie group and that the bundle is a principal bundle. The dependence on the fibre coordinate is consider...

Correspondence: [email protected] UMIACS, University of Maryland, College Park, MD 20742-3275, USA Full list of author information is available at the end of the article †Equal contributor Abstract Shearlets have emerged in recent years as one of of the most successful methods for the multiscale analysis of multidimensional signals. Unlike wavelets, shearlets form a pyramid of well-localize...

This is a nontechnical introduction to recent work on quantum gravity using ideas from higher-dimensional algebra. We argue that reconciling general relativity with the Standard Model requires a ‘background-free quantum theory with local degrees of freedom propagating causally’. We describe the insights provided by work on topological quantum field theories such as quantum gravity in 3-dimensio...

Every finitary monad T on the category of sets is described by an algebraic theory whose n-ary operations are the elements of the free algebra Tn generated by n letters. This canonical presentation of the monad (called its Lawvere theory) offers a precious guideline in the search for an intuitive presentation of the monad by generators and relations. Hence, much work has been devoted to extend ...