Mj. Sevilla et R. Paya, NORM ATTAINING MULTILINEAR FORMS AND POLYNOMIALS ON PREDUALS OF LORENTZ SEQUENCE-SPACES, Studia Mathematica, 127(2), 1998, pp. 99-112
For each natural number N, we give an example of a Banach space X such
that the set of norm attaining N-linear forms is dense in the space o
f all continuous N-linear forms on X, but there are continuous (N + 1)
-linear forms on X which cannot be approximated by norm attaining (N 1)-linear forms. Actually, X is the canonical predual of a suitable L
orentz sequence space. We also get the analogous-result for homogeneou
s polynomials.