Abstract
The aim in this paper is to study algebraic orthogonality between positive elements of a \(C^{*}\)-algebra in the context of geometric orthogonality. It has been shown that the algebraic orthogonality in certain classes of \(C^{*}\)-algebras is equivalent to geometric orthogonality when supported with some order-theoretic conditions. Further more, algebraic orthogonality between positive elements in a \(C^{*}\)-algebra is also characterized in terms of positive linear functionals.
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References
Birkhoff, G.: Orthogonality in linear metric spaces. Duke Math. J. 1, 169–172 (1935)
James, R.C.: Orthogonality in normed linear spaces. Duke Math. J. 12, 291–302 (1945)
Kadison, R.V., Ringrose, J.R.: Fundamentals of the Theory of Operator Algebras, I. Academic Press, New York (1983)
Karn, A.K.: A \(p\)-theory of ordered normed spaces. Positivity 14, 441–458 (2010)
Karn, A.K.: Orthogonality in \(\ell _p\)-spaces and its bearing on ordered normed spaces. Positivity 18, 223–234 (2014)
Oikhberg, T., Peralta, A.M., Ramirez, M.: Automatic continuity of \(M\)-norms on \(C^*\)-algebras. J. Math. Anal. Appl. 381(2), 799–811 (2011)
Oikhberg, T., Peralta, A.M.: Automatic continuity of orthogonality preservers on a non-commutative \(L_p (\tau )\) space. J. Funct. Anal. 264, 1848–1872 (2013)
Pedersen, G.K.: \(C^{\ast }\)-Algebras and Their Automorphism Groups. Academic Press, London (1979)
Raynaud, Y., Xu, Q.: On subspaces of non-commutative \(L^p\)-spaces. J. Funct. Anal. 203, 149–196 (2003)
Acknowledgments
The author is indebted to B. V. R. Bhat and V. S. Sunder for many fruitful discussions. The author is also grateful to the referee for his valuable suggestions.
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Karn, A.K. Orthogonality in \(C^{*}\)-algebras. Positivity 20, 607–620 (2016). https://doi.org/10.1007/s11117-015-0375-z
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DOI: https://doi.org/10.1007/s11117-015-0375-z
Keywords
- Algebraic orthogonality
- Absolute p-orthogonality
- Absolute order smooth p-normed spaces
- Absolute p-orthogonal decomposition