Some basic theorems and formulae (equations and inequalities) of several areas of mathematics that hold in Bernstein spaces are no longer valid in larger spaces. However, when a function f is in some sense close to a Bernstein space, then the corresponding relation holds with a remainder or error term. This paper presents a new, unified approach to these errors in terms of the distance of f from . The difficult situation of derivative-free error estimates is also covered.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-bc102-0-2, author = {P. L. Butzer and R. L. Stens and G. Schmeisser}, title = {Basic relations valid for the Bernstein spaces $B$^2$\_{$\sigma$}$ and their extensions to larger function spaces via a unified distance concept}, journal = {Banach Center Publications}, volume = {102}, year = {2014}, pages = {41-55}, zbl = {1315.42014}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc102-0-2} }
P. L. Butzer; R. L. Stens; G. Schmeisser. Basic relations valid for the Bernstein spaces $B²_{σ}$ and their extensions to larger function spaces via a unified distance concept. Banach Center Publications, Tome 102 (2014) pp. 41-55. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc102-0-2/