Title
On the Quality of First-Order Approximation of Functions with Hölder Continuous Gradient.
Abstract
We show that Hölder continuity of the gradient is not only a sufficient condition, but also a necessary condition for the existence of a global upper bound on the error of the first-order Taylor approximation. We also relate this global upper bound to the Hölder constant of the gradient. This relation is expressed as an interval, depending on the Hölder constant, in which the error of the first-order Taylor approximation is guaranteed to be. We show that, for the Lipschitz continuous case, the interval cannot be reduced. An application to the norms of quadratic forms is proposed, which allows us to derive a novel characterization of Euclidean norms.
Year
DOI
Venue
2020
10.1007/s10957-020-01632-x
Journal of Optimization Theory and Applications
Keywords
DocType
Volume
Hölder continuous gradient, First-order Taylor approximation, Lipschitz continuous gradient, Lipschitz constant, Euclidean norms, 68Q25, 90C30, 90C48
Journal
185
Issue
ISSN
Citations 
1
0022-3239
0
PageRank 
References 
Authors
0.34
0
4
Name
Order
Citations
PageRank
Guillaume O. Berger100.34
Pierre-Antoine Absil200.34
Raphaël M. Jungers322239.39
Yurii Nesterov41800168.77