Geodesic
Negative Results in Form-Preserving Approximation of Higher Order
Matematičeskie zametki, Tome 76 (2004) no. 6, pp. 812-823

Voir la notice de l'article provenant de la source Math-Net.Ru

It is proved that for $q$-convex polynomial approximations, where $q\ge4$ , inequalities of Jackson type are not valid even with a constant depending on the approximated function. 
@article{MZM_2004_76_6_a1,
     author = {A. V. Bondarenko and A. V. Primak},
     title = {Negative {Results} in {Form-Preserving} {Approximation} of {Higher} {Order}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {812--823},
     publisher = {mathdoc},
     volume = {76},
     number = {6},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2004_76_6_a1/}
}
TY  - JOUR
AU  - A. V. Bondarenko
AU  - A. V. Primak
TI  - Negative Results in Form-Preserving Approximation of Higher Order
JO  - Matematičeskie zametki
PY  - 2004
SP  - 812
EP  - 823
VL  - 76
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_2004_76_6_a1/
LA  - ru
ID  - MZM_2004_76_6_a1
ER  - 
%0 Journal Article
%A A. V. Bondarenko
%A A. V. Primak
%T Negative Results in Form-Preserving Approximation of Higher Order
%J Matematičeskie zametki
%D 2004
%P 812-823
%V 76
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_2004_76_6_a1/
%G ru
%F MZM_2004_76_6_a1
A. V. Bondarenko; A. V. Primak. Negative Results in Form-Preserving Approximation of Higher Order. Matematičeskie zametki, Tome 76 (2004) no. 6, pp. 812-823. http://geodesic.mathdoc.fr/item/MZM_2004_76_6_a1/