Abstract
We prove that every infinite-dimensional -algebra satisfies that every slice of the unit ball of (-fold projective symmetric tensor product of ) has diameter two. We deduce that every infinite-dimensional Banach space whose dual is an -space satisfies the same result. As a consequence, if is either a -algebra or either a predual of an -space, then the space of all -homogeneous polynomials on , , is extremely rough, whenever is infinite-dimensional. If is a predual of a von Neumann algebra, then is infinite-dimensional if, and only if, every -slice of the unit ball of (the space of integral -homogeneous polynomials on ) has diameter two. As a consequence, under the previous assumptions, the -fold symmetric injective tensor product of is extremely rough. Indeed, this isometric condition characterizes infinite-dimensional spaces in the class of preduals of von Neumann algebras.
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Published by Heldermann Verlag, 2011. Rights now held by Banach Press.
