Resumen de Chebyshev coefficients for L1-preduals and for spaces with the extension property

Concepción Masa, José Manuel Bayod Bayod

• We apply the Chebyshev coefficients ?f and ?b, recently introduced by the authors, to obtain some results related to certain geometric properties of Banach spaces. We prove that a real normed space E is an L1-predual if and only if ?f(E) = 1/2, and that if a (real or complex) normed space E is a P1 space, then ?b(E) equals ?b(K), where K is the ground field of E.