The extremal elements of the unit balls of Banach spaces play an important role in the study of the geometry of the space as well in various applications. For Banach spaces of Lipschitz real functions the extremal elements of the unit ball are investigates in numerous papers (S. Cobzas 1989, J. D. Farmer 1994, N. V. Rao and A. C. Roy 1970, Roy 1968 and in the references therein). In this note we shall present a procedure to obtain extremal elements of the unit ball of the quasi normed semilinear space of real-valued semi-Lipschitz functions defined on a quasi-metric space.
“Tiberiu Popoviciu” Institute of Numerical Analysis, Romanian Academy, Romania
semi metric spaces; semi Lipschitz real functions.
C. Mustăţa, On the extremal semi-Lipschitz function, Rev. Anal. Numer. Theor. Approx. 31 (2002) no. 1, 103-108.
Revue d’Analyse Numer.Theor. Approx.
Publishing Romanian Academy
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