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Haïkel Skhiri 《Integral Equations and Operator Theory》2008,62(1):137-148
Let be the algebra of all bounded linear operators on a complex Banach space X and γ(T) be the reduced minimum modulus of operator . In this work, we prove that if , is a surjective linear map such that is an invertible operator, then , for every , if and only if, either there exist two bijective isometries and such that for every , or there exist two bijective isometries and such that for every . This generalizes for a Banach space the Mbekhta’s theorem [12].
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Let and be the algebras of all bounded linear operators on infinite dimensional complex Banach spaces X and Y, respectively. We characterize additive maps from onto preserving different quantities such as the nullity, the defect, the ascent, and the descent of operators. 相似文献
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It is proved that a linear transformation on the vector space of upper triangular matrices that maps the set of matrices of minimal rank 1 into itself, and either has the analogous property with respect to matrices of full minimal rank, or is bijective, is a triangular equivalence, or a flip about the south-west north-east diagonal followed by a triangular equivalence. The result can be regarded as an analogue of Marcus–Moyls theorem in the context of triangular matrices. 相似文献
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We describe all linear self-mappings of the space of bounded linear operators in an infinite dimensional separable complex Hilbert space which preserve the isomorphism class of the lattice of invariant operator ranges. 相似文献
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设H为复Hilbert空间,y_a(H)代表H上的有界自伴算子组成的空间,Φ:y_a(H)→y_a(H)是满射且复数ξ,n∈C\{1},则Φ满足W(AB-ξBA)=W(Φ(A)Φ(B)-ηΦ(B)Φ(A))对所有A,B∈y_a(H)成立当且仅当存在酉算子或者共轭酉算子U,使得Φ(A)=UAU*对所有A∈y_a(H)成立,或者Φ(A)=-UAU*对所有A∈y_a(H)成立. 相似文献
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Nik Stopar 《代数通讯》2013,41(6):2053-2065
We describe surjective additive maps θ: A → B which preserve zero products, where A is a ring with a nontrivial idempotent and B is a prime ring. We also characterize surjective additive maps θ: A → B such that for all x, y ∈ A we have θ(x)θ(y)* = 0 if and only if xy* = 0. Here A is a unital prime ring with involution that contains a nontrivial idempotent and B is a prime ring with involution. 相似文献