Properties of Hadamard Directional Derivatives: Denjoy-Young-Saks Theorem for Functions on Banach Spaces
Journal of convex analysis, Tome 22 (2015) no. 1, pp. 161-176
\newcommand{\R}{{\mathbb R}} The classical Denjoy-Young-Saks theorem on Dini derivatives of arbitrary functions $f: \R \to \R$ was extended by U.S. Haslam-Jones (1932) and A.J. Ward (1935) to arbitrary functions on $\R^2$. This extension gives the strongest relation among upper and lower Hadamard directional derivatives $f^+_H (x,v)$, $f^-_H (x,v)$ ($v \in X$) which holds almost everywhere for an arbitrary function $f:\R^2\to \R$. Our main result extends the theorem of Haslam-Jones and Ward to functions on separable Banach spaces.
Classification :
46G05, 26B05
Mots-clés : Hadamard upper and lower directional derivatives, Denjoy-Young-Saks theorem, separable Banach space, Hadamard differentiability, Frechet differentiability, Hadamard subdifferentiability, Frechet subdifferentiability, Gamma-null set, Aronszajn null set
Mots-clés : Hadamard upper and lower directional derivatives, Denjoy-Young-Saks theorem, separable Banach space, Hadamard differentiability, Frechet differentiability, Hadamard subdifferentiability, Frechet subdifferentiability, Gamma-null set, Aronszajn null set
@article{JCA_2015_22_1_JCA_2015_22_1_a8,
author = {L. Zaj{\'\i}cek},
title = {Properties of {Hadamard} {Directional} {Derivatives:} {Denjoy-Young-Saks} {Theorem} for {Functions} on {Banach} {Spaces}},
journal = {Journal of convex analysis},
pages = {161--176},
year = {2015},
volume = {22},
number = {1},
url = {http://geodesic.mathdoc.fr/item/JCA_2015_22_1_JCA_2015_22_1_a8/}
}
TY - JOUR AU - L. Zajícek TI - Properties of Hadamard Directional Derivatives: Denjoy-Young-Saks Theorem for Functions on Banach Spaces JO - Journal of convex analysis PY - 2015 SP - 161 EP - 176 VL - 22 IS - 1 UR - http://geodesic.mathdoc.fr/item/JCA_2015_22_1_JCA_2015_22_1_a8/ ID - JCA_2015_22_1_JCA_2015_22_1_a8 ER -
%0 Journal Article %A L. Zajícek %T Properties of Hadamard Directional Derivatives: Denjoy-Young-Saks Theorem for Functions on Banach Spaces %J Journal of convex analysis %D 2015 %P 161-176 %V 22 %N 1 %U http://geodesic.mathdoc.fr/item/JCA_2015_22_1_JCA_2015_22_1_a8/ %F JCA_2015_22_1_JCA_2015_22_1_a8
L. Zajícek. Properties of Hadamard Directional Derivatives: Denjoy-Young-Saks Theorem for Functions on Banach Spaces. Journal of convex analysis, Tome 22 (2015) no. 1, pp. 161-176. http://geodesic.mathdoc.fr/item/JCA_2015_22_1_JCA_2015_22_1_a8/