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1.
Sobhy El-Sayed Ibrahim 《Czechoslovak Mathematical Journal》2004,54(1):9-29
In this paper, the general ordinary quasi-differential expression M
pof n-th order with complex coefficients and its formal adjoint M
p
+
on any finite number of intervals I
p
=(a
p
,b
p
),p= 1,...,N, are considered in the setting of the direct sums of L
wp
2
(a
p
,b
p
)-spaces of functions defined on each of the separate intervals, and a number of results concerning the location of the point spectra and the regularity fields of general differential operators generated by such expressions are obtained. Some of these are extensions or generalizations of those in a symmetric case in [1], [14], [15], [16], [17] and of a general case with one interval in [2], [11], [12], whilst others are new. 相似文献
2.
A Riesz space K1 whose elements are pairs of convex-set collections is presented for the study on the calculus of generalized quasi-differentiable functions. The space K1 is constructed by introducing a well-defined equivalence relation among pairs of collections of convex sets. Some important properties on the norm and operations in K1 are given. 相似文献
3.
Aboubakr Bayoumi 《Central European Journal of Mathematics》2006,4(4):585-593
We prove that the Quasi Differential of Bayoumi of maps between locally bounded F-spaces may not be Fréchet-Differential and vice versa. So a new concept has been discovered with rich applications (see [1–6]).
Our F-spaces here are not necessarily locally convex 相似文献
4.
5.
Sobhy El-Sayed Ibrahim 《Czechoslovak Mathematical Journal》1999,49(4):877-890
This paper is concerned with square integrable quasi-derivatives for any solution of a general quasi-differential equation of nth order with complex coefficients M[y] – wy = wf(t, y
[0],... , y
[n–1]), t [a, b) provided that all rth quasi-derivatives of solutions of M[y] – wy = 0 and all solutions of its normal adjoint
are in
and under suitable conditions on the function f. 相似文献
6.
Maksim Sokolov 《Central European Journal of Mathematics》2005,3(4):627-643
In the current work a generalization of the famous Weyl-Kodaira inversion formulas for the case of self-adjoint differential
vector-operators is proved. A formula for spectral resolutions over an analytical defining set of solutions is discussed.
The article is the first part of the planned two-part survey on the structural spectral theory of self-adjoint differential
vector-operators in matrix Hilbert spaces.
The work is dedicated to Professor Ravshan Ashurov on occasion of his 50-th anniversary. 相似文献
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