scholarly journals Shift invariant operators and a saturation theorem

2003 ◽  
Vol 30 (3) ◽  
pp. 267-286
Author(s):  
Karol Dziedziul
Keyword(s):  
2015 ◽  
Vol 60 (3) ◽  
pp. 1987-1992
Author(s):  
M. Nabiałek

AbstractThis work presents the results of investigations into the structural and magnetic properties of the bulk amorphous alloy: Fe64Co10Y6B20. The structure, thermal stability and magnetic properties of the alloy were studied using: X-ray diffractometry, differential scanning calorimetry (DSC), and a vibrating sample magnetometer (VSM), respectively. The investigations were performed on samples of the alloy in both the ‘as-cast’ state, and the state resulting from a process of isothermal annealing at a temperature of 750 K for 30 minutes.The aim of the conducted studies was to relax the structure and improve the soft magnetic properties of the investigated alloy. The results show that annealing the alloy at a temperature well below its crystallisation temperature leads to an increase in the value of the saturation magnetisation and a decrease in the value of the coercivity. Utilising the ‘approach to the ferromagnetic saturation’ theorem, the nature of structural defects within the investigated material has been established. For both ‘as-cast’ and isothermally-annealed samples, the magnetisation process has been found to be connected with the existence of linear structural defects.


1972 ◽  
Vol 24 (5) ◽  
pp. 957-966 ◽  
Author(s):  
G. J. Butler ◽  
F. B. Richards

Let 1 be a subdivision of [0, 1], and let denote the class of functions whose restriction to each sub-interval is a polynomial of degree at most k. Gaier [1] has shown that for uniform subdivisions △n (that is, subdivisions for which if and only if f is a polynomial of degree at most k. Here, and subsequently, denotes the usual norm in Lp[0, 1], 1 ≦ p ≦ ∞, and we should emphasize that functions differing only on a set of Lebesgue measure zero are identified.


1991 ◽  
Vol 01 (01) ◽  
pp. 211-217 ◽  
Author(s):  
MORRIS W. HIRSCH

We consider a broad class of continuous time dynamical systems modeling a collection of processing units sending signals to each other. Each unit has an internal state variable xi and an output variable yi which is a nondecreasing function gi (xi). Certain outputs, called "forced", are of the form σj (Kxj) where σj is a sigmoid and K > 0 is a parameter called "gain". The dynamics is given by a system of differential equations of the form dx/dt = H (x, y, t). The system is self-exciting: ∂Hi/∂yi ≥ 0, and > 0 for the forced outputs. We show that for sufficiently high gain, the forced outputs are close to the asymptotic limiting values of the sigmoids along any stable solution x (t) defined on a finite interval J, for a proportion of t ∈ J that approaches 1 as K → ∞. This generalizes Hopfield's Saturation Theorem about additive neural networks with symmetric weight matrices.


2013 ◽  
Vol 149 (9) ◽  
pp. 1569-1582 ◽  
Author(s):  
David Anderson ◽  
Edward Richmond ◽  
Alexander Yong

AbstractThe saturation theorem of Knutson and Tao concerns the nonvanishing of Littlewood–Richardson coefficients. In combination with work of Klyachko, it implies Horn’s conjecture about eigenvalues of sums of Hermitian matrices. This eigenvalue problem has a generalization to majorized sums of Hermitian matrices, due to S. Friedland. We further illustrate the common features between these two eigenvalue problems and their connection to Schubert calculus of Grassmannians. Our main result gives a Schubert calculus interpretation of Friedland’s problem, via equivariant cohomology of Grassmannians. In particular, we prove a saturation theorem for this setting. Our arguments employ the aforementioned work together with recent work of H. Thomas and A. Yong.


1996 ◽  
Vol 29 (1) ◽  
Author(s):  
Vijay Gupta ◽  
G. S. Srivastava

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