The Levi graph of a balanced incomplete block design is the bipartite graph whose vertices are the points and blocks of the design, with each block adjacent to those points it contains. We derive upper and lower bounds on the isoperimetric numbers of such graphs, with particular attention to the special cases of finite projective planes and Hadamard designs.

Levi-Montalcini and her twin sister Paola were born on 22 April 1909 in Turin, Italy, to her father, Adamo Levi, an electrical engineer and mathematician, and mother, Adele Montalcini. In her autobiography she describes her family atmosphere as wonderful, loving, and with reciprocal devotion. Her father was a very traditional man and his daughters were not allowed to pursue a professional caree...

Isaac Levi's philosophical thinking has shown remarkable stability over the years. Basically, it all started with his first book, Gambling with Truth, which outlines a research program whose key element is the decision theoretic reconstruction of epistemology. Much of the rest of his work in epistemology has been devoted to extending and implementing this original program. With one important ex...

www.expert-reviews.com © 2012 Expert Reviews Ltd ISSN 1747-6348 10.1586/ERS.11.81 Any impairment in striated muscle function can interfere with the performance of daily activities, particularly for a patient already living with a respiratory disorder. However, the interaction between the respiratory and musculoskeletal systems is not always considered in the clinical management of these patient...

Purpose: Amblyopia is a developmental disorder of spatial vision for which there is no positive diagnostic test. The present study evaluates the recently developed “Pelli-Levi Dual Acuity Chart” as a positive diagnostic test for amblyopia (Pelli, Levi & Chung, 2004). This chart consists of letters, as usual, on one side and letters in noise on the other. This exploits the finding that, for lett...

A Schubert variety in the complete flag manifold $$GL_n/B$$ is Levi-spherical if action of a Borel subgroup Levi standard parabolic has an open dense orbit. We give combinatorial classification these varieties. This establishes conjecture latter two authors, and new formulation terms Coxeter elements. Our proof uses contributes to theory key polynomials (type Demazure module characters).

Levi-properties were first introduced by L. C. Kappe and are modeled after groups investigated by F. W. Levi where conjugates commute. Let X be a group theoretic class. A group is in the derived class L(X) if the normal closure of each element in the group is an X -group. The property of being in the class L (X) is called the Levi-property generated by X . In the case where X is a variety, we s...

Power series with rational exponents on the real numbers field and the Levi-Civita field are studied. We derive a radius of convergence for power series with rational exponents over the field of real numbers that depends on the coefficients and on the density of the exponents in the series. Then we generalize that result and study power series with rational exponents on the Levi-Civita field. A...