University of Wyoming Open Journals
Not a member yet
3193 research outputs found
Sort by
Upper Bound for the Number of Distinct Eigenvalues of a Perturbed Matrix
No full textIn 2016, Farrell presented an upper bound for the number of distinct eigenvalues of a perturbed matrix. Xu (2017), and Wang and Wu (2016) introduced upper bounds which are sharper than Farrell's bound. In this paper, the upper bounds given by Xu, and Wang and Wu are improved
On the distance and distance signless Laplacian eigenvalues of graphs and the smallest Gersgorin disc
No full textThe \emph{distance matrix} of a simple connected graph is , where is the distance between the th and th vertices of . The \emph{distance signless Laplacian matrix} of the graph is , where is a diagonal matrix whose th diagonal entry is the transmission of the vertex in . In this paper, first, upper and lower bounds for the spectral radius of a nonnegative matrix are constructed. Applying this result, upper and lower bounds for the distance and distance signless Laplacian spectral radius of graphs are given, and the extremal graphs for these bounds are obtained. Also, upper bounds for the modulus of all distance (respectively, distance signless Laplacian) eigenvalues other than the distance (respectively, distance signless Laplacian) spectral radius of graphs are given. These bounds are probably first of their kind as the authors do not find in the literature any bound for these eigenvalues. Finally, for some classes of graphs, it is shown that all distance (respectively, distance signless Laplacian) eigenvalues other than the distance (respectively, distance signless Laplacian) spectral radius lie in the smallest Gerˆsgorin disc of the distance (respectively, distance signless Laplacian) matrix
Iteration with Stepsize Parameter and Condition Numbers for a Nonlinear Matrix Equation
No full textIn this paper, the nonlinear matrix equation , where is a positive integer, is an arbitrary matrix, and is a symmetric positive definite matrix, is considered. A fixed-point iteration with stepsize parameter for obtaining the symmetric positive definite solution of the matrix equation is proposed. The explicit expressions of the normwise, mixed and componentwise condition numbers are derived. Several numerical examples are presented to show the efficiency of the proposed iterative method with proper stepsize parameter and the sharpness of the three kinds of condition numbers
Discontinuity Propagation in Delay Differential-Algebraic Equations
No full textThe propagation of primary discontinuities in initial value problems for linear delay differential-algebraic equations (DDAEs) is discussed. Based on the (quasi-) Weierstra{\ss} form for regular matrix pencils, a complete characterization of the different propagation types is given and algebraic criteria in terms of the matrices are developed. The analysis, which is based on the method of steps, takes into account all possible inhomogeneities and history functions and thus serves as a worst-case scenario. Moreover, it reveals possible hidden delays in the DDAE and allows to study exponential stability of the DDAE based on the spectral abscissa. The new classification for DDAEs is compared to existing approaches in the literature and the impact of splicing conditions on the classification is studied
Determinantal Properties of Generalized Circulant Hadamard Matrices
No full textThe derivation of analytical formulas for the determinant and the minors of a given matrix is in general a difficult and challenging problem. The present work is focused on calculating minors of generalized circulant Hadamard matrices. The determinantal properties are studied explicitly, and generic theorems specifying the values of all the minors for this class of matrices are derived. An application of the derived formulae to an interesting problem of numerical analysis, the growth problem, is also presented
Effects of sagebrush restoration on plant and bird communities in Grand Teton National Park
No full textApproximately half of sagebrush steppe range-wide has been converted to non-native grasslands, which has contributed to population declines of sagebrush-associated songbirds. Removal of non-native grasses and restoration treatments are time-, resource- and energy-intensive, but could lead to the return of functional habitat for sagebrush wildlife. The extent to which restoration efforts repair the structure and functionality of sagebrush steppe for different types of wildlife, however, remains largely untested. To determine breeding songbird community responses to sagebrush restoration treatments, we are conducting a longitudinal study with sampling every 5 years within restoration units at different stages of restoration in the Kelly Hayfields restoration area in Grand Teton National Park, Wyoming. Thus far, in 2013 and 2018 we compared bird and plant communities in unrestored (largely smooth brome [Bromus inermis]) units to those in various stages of restoration treatments, and to areas of native sagebrush. The sagebrush plots will serve as desired comparators for the endpoints of restoration efforts. The in-progress and recently replanted units were either dominated by bare ground (following herbicidal application) or native forbs with very little shrub cover (< 0.1%). Native sagebrush units were dominated by shrubs and native bunchgrasses. Bird community composition was distinct among the different unit types. Abundance of grassland birds was highest in unrestored units, whereas the abundance of shrubland birds was highest in native sagebrush and positively associated with shrub cover. There were very few detections of birds in recently re-seeded units. Restored areas may initially provide little breeding bird habitat, especially prior to the establishment of native bunch grasses and a mature shrub layer. Plant and bird sampling efforts will continue every five years to document how plant and bird assemblages shift over time in response to restoration efforts.
Featured photo by Matt Lavin on Flickr. https://flic.kr/p/fh7UJ
Brutal Youth: Colin MacInnes and the Architecture of the Welfare State
No full textColin MacInnes’ London trilogy is known for its prominent focus—unusual in British fiction of the time—on class and racial conflict in mid-century London. Comprised of City of Spades (1957), Absolute Beginners (1959), and Mr Love and Justice (1960), the trilogy plots the complicated enactment of the new welfare-state’s reconstruction strategies from the post-war resurgence of slum clearance, to the forced evictions of suburban migration, to the development and erection of alienating council flats. In doing so, MacInnes offers a distinctive take on Londoners’ responses to these strategies, demonstrating the way mindful urban planning was shouldered aside by quixotic and hurried resolutions. As part of a vibrant wave of mid-century British writing sensitive to issues of class, race, and gender, MacInnes’ fiction scrutinized postwar urban displacement as it happened and without any of the benefit of hindsight. This article, then, highlights the distinctively nuanced perspectives that socially-attuned and classconscious literature can offer in terms of understanding the tangible impact of space on social stratification
I Was a Retail Salesperson: An Examination of Two Memoirs About Working in Retail
No full textThis article considers Barbara Ehrenreich’s Nickel and Dimed (originally published in 2001) and Caitlin Kelly’s Malled (2011) as representational narratives of working-class retail workers. The display of working-class experience in each work is considered in the context of the authors’ lives and experiences, considering use of language, events and broader expectations of the working life of retail salespeople. Using Stuart Hall’s concept of the ‘Other’ (2013) as a theoretical key point, the article also considers, for an American perspective specifically, how these workers are constructed in the broader ideology of the nation state
Preface: International Conference on Matrix Analysis and Its Applications -- MatTriad 2017
No full textDeterminants of Interval Matrices
No full textIn this paper we shed more light on determinants of real interval matrices. Computing the exact bounds on a determinant of an interval matrix is an NP-hard problem. Therefore, attention is first paid to approximations. NP-hardness of both relative and absolute approximation is proved. Next, methods computing verified enclosures of interval determinants and their possible combination with preconditioning are discussed. A new method based on Cramer's rule was designed. It returns similar results to the state-of-the-art method, however, it is less consuming regarding computational time. Other methods transferable from real matrices (e.g., the Gerschgorin circles, Hadamard's inequality) are discussed. New results about classes of interval matrices with polynomially computable tasks related to determinant are proved (symmetric positive definite matrices, class of matrices with identity midpoint matrix, tridiagonal H-matrices). The mentioned methods were compared for random general and symmetric matrices