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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Preservation Of The Range Under Perturbations Of An Operator, Branko Ćurgus, Branko Najman
Preservation Of The Range Under Perturbations Of An Operator, Branko Ćurgus, Branko Najman
Mathematics Faculty Publications
A sufficient condition for the stability of the range of a positive operator in a Hilbert space is given. As a consequence, we get a class of additive perturbations which preserve regularity of the critical point 0 of a positive operator in a Krein space.
Discrete Tomography: Determination Of Finite Sets By X-Rays, Richard J. Gardner, Peter Gritzmann
Discrete Tomography: Determination Of Finite Sets By X-Rays, Richard J. Gardner, Peter Gritzmann
Mathematics Faculty Publications
We study the determination of finite subsets of the integer lattice Zn, n ≥ 2, by X-rays. In this context, an X-ray of a set in a direction u gives the number of points in the set on each line parallel to u. For practical reasons, only X-rays in lattice directions, that is, directions parallel to a nonzero vector in the lattice, are permitted. By combining methods from algebraic number theory and convexity, we prove that there are Sour prescribed lattice directions such that convex subsets of Zn (i.e., finite subsets F with F = Z …
Short-Lived Intermediates In Aspartate Aminotransferase Systems, George Czerlinski, Richard Levin, Tjalling Ypma
Short-Lived Intermediates In Aspartate Aminotransferase Systems, George Czerlinski, Richard Levin, Tjalling Ypma
Mathematics Faculty Publications
The kinetics of the reaction of aspartate aminotransferase with erythro-beta-hydroxy-aspartate, in which rapid mixing is followed (upon reaching a suitable stationary state) by a very fast temperature jump, is numerically simulated. Values for rate constants are used to the extent known, otherwise estimated. It is shown that reaction steps not resolvable by rapid mixing can be resolved by subsequent chemical relaxation. Since several absorption spectra of enzyme complexes overlap, use of a pH-indicator is investigated. When the pH-indicator is coupled to the protonic dissociation of free enzyme, the fast steps are easily detected in the chemical relaxation portion of the …
The Duals Of Warfield Groups, Peter Loth
The Duals Of Warfield Groups, Peter Loth
Mathematics Faculty Publications
A Warfield group is a direct summand of a simply presented abelian group. In this paper, we describe the Pontrjagin dual groups of Warfield groups, both for the p-local and the general case. A variety of characterizations of these dual groups is obtained. In addition, numerical invariants are given that distinguish between two such groups which are not topologically isomorphic.
Normal Lattices And Coseparation Of Lattices, Barry B. Mittag
Normal Lattices And Coseparation Of Lattices, Barry B. Mittag
Mathematics Faculty Publications
No abstract provided.
Integrable Smooth Planar Billiards And Evolutes, Edoh Y. Amiran
Integrable Smooth Planar Billiards And Evolutes, Edoh Y. Amiran
Mathematics Faculty Publications
Any elliptic region is an example of an integrable domain: the set of tangents to a confocal ellipse or hyperbola remains invariant under reflection across the normal to the boundary. The main result states that when Ω is a strictly convex bounded planar domain with a smooth boundary and is integrable near the boundary, its boundary is necessarily an ellipse. The proof is based on the fact that ellipses satisfy a certain “transitivity property”, and that this characterizes ellipses among smooth strictly convex closed planar curves. To establish the transitivity property, KAM theory is used with a perturbation of the …
Positive Solutions And Nonlinear Multipoint Conjugate Eigenvalue Problems, Paul W. Eloe, Johnny Henderson
Positive Solutions And Nonlinear Multipoint Conjugate Eigenvalue Problems, Paul W. Eloe, Johnny Henderson
Mathematics Faculty Publications
Values of λ are determined for which there exist solutions in a cone of the nth order nonlinear differential equation (see PDF) satisfying themultipoint boundary conditions (see PDF) where a and f are nonnegative valued, and where both (see PDF) exist.
Singular Nonlinear (N-1,1) Conjugate Boundary Value Problems, Paul W. Eloe, Johnny Henderson
Singular Nonlinear (N-1,1) Conjugate Boundary Value Problems, Paul W. Eloe, Johnny Henderson
Mathematics Faculty Publications
Solutions are obtained for the boundary value problem, y (n) + f(x,y) = 0, y (i)(0) = y(1) = 0, 0 i n – 2, where f(x,y) is singular at y = 0. An application is made of a fixed point theorem for operators that are decreasing with respect to a cone.
A Boundary Value Problem For A System Of Ordinary Differential Equations With Impulse Effects, Paul W. Eloe, Johnny Henderson
A Boundary Value Problem For A System Of Ordinary Differential Equations With Impulse Effects, Paul W. Eloe, Johnny Henderson
Mathematics Faculty Publications
A two-point boundary value problem for a system of first-order ordinary differential equations with impulse effects is studied. The method of upper and lower solutions is employed to obtain the existence of a solution and a method of forced monotonicity is employed to obtain iterative improvement. The main result is illustrated with an application to the Liénard equation with periodic boundary conditions.