Aequationes Mathematicae ( IF 0.8 ) Pub Date : 2021-03-16 , DOI: 10.1007/s00010-021-00790-1 Michael Frank , Mohammad Sal Moslehian , Ali Zamani
We investigate the orthogonality preserving property for pairs of operators on inner product \(C^*\)-modules. Employing the fact that the \(C^*\)-valued inner product structure of a Hilbert \(C^*\)-module is determined essentially by the module structure and by the orthogonality structure, pairs of linear and local orthogonality-preserving operators are investigated, not a priori bounded. We obtain that if \({\mathscr {A}}\) is a \(C^{*}\)-algebra and \(T, S:{\mathscr {E}}\rightarrow {\mathscr {F}}\) are two bounded \({{\mathscr {A}}}\)-linear operators between full Hilbert \({\mathscr {A}}\)-modules, then \(\langle x, y\rangle = 0\) implies \(\langle T(x), S(y)\rangle = 0\) for all \(x, y\in {\mathscr {E}}\) if and only if there exists an element \(\gamma \) of the center \(Z(M({{\mathscr {A}}}))\) of the multiplier algebra \(M({{\mathscr {A}}})\) of \({{\mathscr {A}}}\) such that \(\langle T(x), S(y)\rangle = \gamma \langle x, y\rangle \) for all \(x, y\in {\mathscr {E}}\). Varying the conditions on the operators T and S we obtain further affirmative results for local operators and for pairs of a bounded and an unbounded \({{\mathscr {A}}}\)-linear operator with bounded inverse.
中文翻译:
Hilbert $$ C ^ * $$ C ∗ -modules上的算子对的正交保留性质
我们研究内积\(C ^ * \)-模块上算子对的正交性。利用一个事实,希尔伯特\(C ^ * \)-模块的\(C ^ * \)值内积结构基本上由模块结构和正交性结构,线性和局部正交性对确定对运算符进行了调查,而不是先验地界。如果\({\ mathscr {A}} \)是\(C ^ {*} \)-代数和\(T,S:{\ mathscr {E}} \ rightarrow {\ mathscr {F} } \)是完整Hilbert \({{mathscr {A}} \)-)模块之间的两个有界\({{\ mathscr {A}}} \)-线性算子,然后\(\ langle x,y \ rangle = 0 \)表示\ {x,y \ in {\ mathscr {E}}中的所有\(\ langle T(x),S(y)\ rangle = 0 \))当且仅当存在一个元素(\伽马\)\中心的ž\((M - ({{\ mathscr {A}}}))\)乘法器代数\(M({{\ mathscr { A}}})\)的\({{\ mathscr {A}}} \),使得\(\ langle T(X),S(y)的\ rangle = \伽马\ langle的x,y \ rangle \)对于所有\(x,y \ in {\ mathscr {E}} \)。改变运算符T和S的条件,我们将为本地运算符以及有界和无界\({{\ mathscr {A}}} \)对获得进一步的肯定结果-有界逆的线性算子。