We find the norm of the Hardy operator minus the identity acting on the cone of radially decreasing functions on minimal Lorentz spaces (restricted type estimates).
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm197-1-6, author = {Javier Soria}, title = {Optimal bounds of restricted type for the Hardy operator minus the identity on the cone of radially decreasing functions}, journal = {Studia Mathematica}, volume = {196}, year = {2010}, pages = {69-79}, zbl = {1217.26036}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm197-1-6} }
Javier Soria. Optimal bounds of restricted type for the Hardy operator minus the identity on the cone of radially decreasing functions. Studia Mathematica, Tome 196 (2010) pp. 69-79. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm197-1-6/