Abstract.
We prove that, given a real JB*-triple X, there exists a nonempty relatively weakly open subset of the closed unit ball of X with diameter less than 2 (if and) only if the Banach space of X is isomorphic to a Hilbert space. Moreover we give the structure of real JB*-triples whose Banach spaces are isomorphic to Hilbert spaces. Such real JB*-triples are also characterized in two different purely algebraic ways.
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Mathematics Subject Classification (2000): 46B04, 46B22, 46L05, 46L70
Partially supported by Junta de Andalucía grant FQM 0199.
Revised version: 30 September 2003
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Guerrero, J., Pérez, G., Peralta, A. et al. Relatively weakly open sets in closed balls of Banach spaces, and real JB*-triples of finite rank. Math. Ann. 330, 45–58 (2004). https://doi.org/10.1007/s00208-004-0537-y
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DOI: https://doi.org/10.1007/s00208-004-0537-y