Abstract
We prove a Kadec-Pelczyński dichotomy-type theorem for bounded sequences in the predual of a JBW*-algebra, showing that for each bounded sequence (ϕ n ) in the predual of a JBW*-algebra M, there exist a subsequence (ϕ τ(n), and a sequence of mutually orthogonal projections (p n ) in M such that:
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(a)
the set \(\{ {\phi _{\tau (n)}} - {\phi _{\tau (n)}}{P_2}({p_n}):n \in {\Bbb N}\} \) is relatively weakly compact
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(b)
ϕ τ(n) = ξ n + ψ n , with ξ n := ϕ τ(n) − ϕ τ(n) P 2(p n ), and ψ n := ϕ τ(n) P 2(p n ), (ξ n Q(p n ) = 0 and ψ n Q(p n )2 = ψ n ) for every n.
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References
C. A. Akemann, The dual space of an operator algebra, Transactions of the American Mathematical Society 126 (1967), 286–302.
C. A. Akemann, P. G. Dodds and J. L. B. Gamlen, Weak compactness in the dual space of C*-algebra, Journal of Functional Analysis 10 (1972), 446–450.
E. M. Alfsen and F. W. Shultz, Geometry of State Spaces of Operator Algebras, Birkhäuser Boston, Boston, MA, 2003.
J. Becerra-Guerrero, G. López, A. M. Peralta and A. Rodríguez-Palacios, Relatively weakly open sets in closed unit balls of Banach spaces, and real JB*-triples of finite rank, Mathematische Annalen 330 (2004), 45–58
J. K. Brooks, K. Saitô and J. D. M. Wright, A bounded sequence of normal functionals has a subsequence which is nearly weakly convergent, Journal of Mathematical Analysis and Applications 276 (2002), 160–167.
L. J. Bunce, Norm preserving extensions in JBW*-triple, Quarterly Journal of Mathematics 52 (2001), 133–136.
L. J. Bunce and C.-H. Chu, Compact operations, multipliers and Radon-Nikodym property in JB*-triples, Pacific Journal of Mathematics 153 (1992), 249–265.
Ch.-H. Chu, Jordan Structures in Geometry and Analysis, Cambridge Tracts in Mathematics, Vol. 190, Cambridge University Press, Cambridge, 2012.
J. Diestel, Sequences and Series in Banach Spaces, Graduate Texts in Mathematics, Vol. 92, Springer-Verlag, New York, 1984.
T. Figiel, N. Ghoussoub and W. B. Johnson, On the structure of nonweakly compact operators on Banach lattices, Mathematische Annalen 257 (1981), 317–334.
Y. Friedman and B. Russo, Structure of the predual of a JBW*-triple, Journal für die Reine und Angewandte Mathematik 356 (1985), 67–89.
H. Hanche-Olsen and E. Størmer, Jordan Operator Algebras, Monographs and Studies in Mathematics, Vol. 21, Pitman, Boston, MA, 1984.
T. Ho, J. Martinez-Moreno, A. M. Peralta and B. Russo, Derivations on real and complex JB*-triples, Journal of the London Mathematical Society 65 (2002), 85–102.
B. Iochum, Cônes autopolaires et algebres de Jordan, Lecture Notes in Mathematics, Vol. 1049, Springer, Berlin-Heidelberg-New York, 1984.
M. I. Kadec and A. Pelczyński, Bases, lacunary sequences and complemented subspaces in the spaces L p, Studia Mathematica 21 (1962), 161–176.
M. Neal, Inner ideals and facial structure of the quasi-state space of a JB-algebra, Journal of Functional Analysis 173 (2000), 284–307.
A. M. Peralta, Some remarks on weak compactness in the dual space of a JB*-triple, Tohoku Mathematical Journal 58 (2006), 149–159.
A. M. Peralta and A. Rodríguez Palacios, Grothendieck’s inequalities for real and complex JBW*-triples, Proceedings of the London Mathematical Society 83 (2001), 605–625.
H. Pfitzner, L-embedded Banach spaces and measure topology, Israel Journal of Mathematics online (2014), DOI: 10.1007/s11856-014-1136-6.
N. Randrianantoanina, Kadec-Pelczyński decomposition for Haagerup L p-spaces, Mathematical Proceedings of the Cambridge Philosophical Society 132 (2002), 137–154.
N. Randrianantoanina, Sequences in non-commutative L p-spaces, Journal of Operator Theory 48 (2002), 255–272.
Y. Raynaud and Q. Xu, On subspaces of non-commutative L p-spaces, Journal of Functional Analysis 203 (2003), 149–196.
K. Saitô, On the preduals of W*-algebras, Tohoku Mathematical Journal 19 (1967), 324–331.
S. Sakai, C*-algebras and W*-algebras, Ergebnisse der Mathematik und ihrer Grenzgebiete, Vol. 60, Springer-Verlag, New York-Heidelberg, 1971.
M. Takesaki, On the conjugate space of operator algebra, Tohoku Mathematical Journal 10 (1958), 194–203.
M. Takesaki, Theory of Operator Algebras. I, Springer-Verlag, New York-Heidelberg, 1979.
D. Topping, Jordan Algebras of Self-Adjoint Operators, Memoirs of the American Mathematical Society 53 (1965).
J. D. M. Wright, Jordan C*-algebras, Michigan Mathematical Journal 24 (1977), 291–302.
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First and second authors partially supported by the Spanish Ministry of Economy and Competitiveness, D.G.I. project no. MTM2011-23843, and Junta de Andalucía grants FQM0199 and FQM3737.
Third author supported partially supported by the Spanish Ministry of Economy and Competitiveness project no. MTM2010-17687.
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Fernández-Polo, F.J., Peralta, A.M. & Ramírez, M.I. A Kadec-Pelczyński dichotomy-type theorem for preduals of JBW*-algebras. Isr. J. Math. 208, 45–78 (2015). https://doi.org/10.1007/s11856-015-1193-5
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DOI: https://doi.org/10.1007/s11856-015-1193-5