caa a22 4500 469068981 CHVBK 20180323132916.0 cr unu---uuuuu 170328e19920201xx s 000 0 eng 10.1007/BF02801572 doi (NATIONALLICENCE)springer-10.1007/BF02801572 Zhou S. Department of Mathematics, Statistics and Computing Science, Dalhousie University, B3H 3J5, Halifax, Nova Scotia, Canada aut A counterexample in copositive approximation [Elektronische Daten] [S. Zhou] The present paper gives a converse result by showing that there exists a functionf ∈C [−1,1], which satisfies that sgn(x)f(x) ≥ 0 forx ∈ [−1, 1], such that {fx75-1} whereE n (0) (f, 1) is the best approximation of degreen tof by polynomials which are copositive with it, that is, polynomialsP withP(x(f(x) ≥ 0 for allx ∈ [−1, 1],E n(f) is the ordinary best polynomial approximation off of degreen. The Magnes Press, 1992 Israel Journal of Mathematics Springer-Verlag 78/1(1992-02-01), 75-83 0021-2172 78:1<75 1992 78 11856 https://doi.org/10.1007/BF02801572 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02801572 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Zhou S. Department of Mathematics, Statistics and Computing Science, Dalhousie University, B3H 3J5, Halifax, Nova Scotia, Canada aut NATIONALLICENCE 773 0- Israel Journal of Mathematics Springer-Verlag 78/1(1992-02-01), 75-83 0021-2172 78:1<75 1992 78 11856 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer