Geodesic
On the relationship between differentiability conditions and existence of a strong gradient
Matematičeskie zametki, Tome 77 (2005) no. 1, pp. 93-98

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

It is proved that for any $n\geqslant2$ there exists continuous function $f\colon\mathbb R^n\to\mathbb R$ which is differentiable almost everywhere, but has no strong gradient almost everywhere. 
@article{MZM_2005_77_1_a7,
     author = {G. G. Oniani},
     title = {On the relationship between differentiability conditions and existence of a strong gradient},
     journal = {Matemati\v{c}eskie zametki},
     pages = {93--98},
     publisher = {mathdoc},
     volume = {77},
     number = {1},
     year = {2005},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2005_77_1_a7/}
}
TY  - JOUR
AU  - G. G. Oniani
TI  - On the relationship between differentiability conditions and existence of a strong gradient
JO  - Matematičeskie zametki
PY  - 2005
SP  - 93
EP  - 98
VL  - 77
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_2005_77_1_a7/
LA  - ru
ID  - MZM_2005_77_1_a7
ER  - 
%0 Journal Article
%A G. G. Oniani
%T On the relationship between differentiability conditions and existence of a strong gradient
%J Matematičeskie zametki
%D 2005
%P 93-98
%V 77
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_2005_77_1_a7/
%G ru
%F MZM_2005_77_1_a7
G. G. Oniani. On the relationship between differentiability conditions and existence of a strong gradient. Matematičeskie zametki, Tome 77 (2005) no. 1, pp. 93-98. http://geodesic.mathdoc.fr/item/MZM_2005_77_1_a7/