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Weakly k-hyponormal and polynomially hyponormal commuting operator pairs
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作者 DUAN Yong Jiang QI Ting Ting 《Science China Mathematics》 SCIE CSCD 2015年第2期405-422,共18页
We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and subnormality.We provide examples... We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and subnormality.We provide examples of 2-variable weighted shifts which are weakly 1-hyponormal but not hyponormal.By relating the weak k-hyponormality and k-hyponormality of a commuting operator pair to positivity of restriction of some linear functionals to corresponding cones of functions,we prove that there is an operator pair that is polynomially hyponormal but not 2-hyponormal,generalizing Curto and Putinar’s result(1991,1993)to the two-variable case. 展开更多
关键词 weakly k-hyponormal k-hyponormal polynomially hyponormal SUBNORMAL commuting operator pair
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Comprehensive Evaluation Model of Reservoir Operation Based on Improved Set Pair Analysis 被引量:4
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作者 任炳昱 孙宜超 +2 位作者 周正印 程正飞 胡兴富 《Transactions of Tianjin University》 EI CAS 2013年第1期25-28,共4页
A comprehensive evaluation model based on improved set pair analysis is established. Considering the complexity in decision-making process, the model combines the certainties and uncertainties in the schemes, i.e., id... A comprehensive evaluation model based on improved set pair analysis is established. Considering the complexity in decision-making process, the model combines the certainties and uncertainties in the schemes, i.e., identical degree, different degree and opposite degree. The relations among different schemes are studied, and the traditional way of solving uncertainty problem is improved. By using the gray correlation to determine the difference degree, the problem of less evaluation indexes and inapparent linear relationship is solved. The difference between the evaluation parameters is smaller in both the fuzzy comprehensive evaluation model and fuzzy matter-element method, and the dipartite degree of the evaluation result is unobvious. However, the difference between each integrated connection degree is distinct in the improved set pair analysis. Results show that the proposed method is feasible and it obtains better effects than the fuzzy comprehensive evaluation method and fuzzy matter-element method. 展开更多
关键词 set pair analysis comprehensive evaluation model gray correlation reservoir operation
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COMMON FIXED POINTS WITH APPLICATIONS TO BEST SIMULTANEOUS APPROXIMATIONS
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作者 Sumit Chandok T. D. Narang 《Analysis in Theory and Applications》 2012年第1期1-12,共12页
For a subset K of a metric space (X,d) and x ∈ X,Px(x)={y ∈ K : d(x,y) = d(x,K)≡ inf{d(x,k) : k ∈ K}}is called the set of best K-approximant to x. An element go E K is said to be a best simulta- neous ... For a subset K of a metric space (X,d) and x ∈ X,Px(x)={y ∈ K : d(x,y) = d(x,K)≡ inf{d(x,k) : k ∈ K}}is called the set of best K-approximant to x. An element go E K is said to be a best simulta- neous approximation of the pair y1,y2 E ∈ if max{d(y1,go),d(y2,go)}=inf g∈K max {d(y1,g),d(y2,g)}.In this paper, some results on the existence of common fixed points for Banach operator pairs in the framework of convex metric spaces have been proved. For self mappings T and S on K, results are proved on both T- and S- invariant points for a set of best simultaneous approximation. Some results on best K-approximant are also deduced. The results proved generalize and extend some results of I. Beg and M. Abbas^[1], S. Chandok and T.D. Narang^[2], T.D. Narang and S. Chandok^[11], S.A. Sahab, M.S. Khan and S. Sessa^[14], P. Vijayaraju^[20] and P. Vijayaraju and M. Marudai^[21]. 展开更多
关键词 Banach operator pair best approximation demicompact fixed point STAR-SHAPED NONEXPANSIVE asymptotically nonexpansive and uniformly asymptot-ically regular maps
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Decomposition Formulas of Kampé de Fériets Double Hypergeometric Functions
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作者 Maged G.Bin-Saad Anvar Hasanov Mamasali Turaev 《Analysis in Theory and Applications》 CSCD 2018年第3期275-292,共18页
This paper is sequel to the authors paper [18]. By using the generalized Burchnall-Chaundy operator method, the authors are aiming at deriving certain decomposition formulas for some interesting special cases of Kampe... This paper is sequel to the authors paper [18]. By using the generalized Burchnall-Chaundy operator method, the authors are aiming at deriving certain decomposition formulas for some interesting special cases of Kampe de Feriets series of double hypergeometric series F;. 展开更多
关键词 Generalized hypergeometric function Kampéde Fériets functions decomposition formulas inverse pairs of symbolic operators
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Symplectic Structures of Two Kinds of Nonsymmetric Differential Operators
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作者 Wei-hua YANG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2015年第2期543-556,共14页
Non-self-adjoint quasi-differential expression M and its formal adjoint M+may generate nonsymmetric ordinary differential operators. Although minimal operators T0, T+0 generated by M, M+are not symmetric, they form... Non-self-adjoint quasi-differential expression M and its formal adjoint M+may generate nonsymmetric ordinary differential operators. Although minimal operators T0, T+0 generated by M, M+are not symmetric, they form an adjoint pair. In this paper, author studies regularly solvable operators with respect to the adjoint pair T0, T+0 in two kinds of conditions and give their geometry description in the corresponding ways. 展开更多
关键词 regularly solvable operators symplectic space self-adjoint operator pair
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