Institution: | Department of Mathematics, School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan ; Department of Mathematics, School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan |
Abstract: | We study Trudinger type inequalities in and their best exponents . We show for , ( is the surface area of the unit sphere in ), there exists a constant such that ![\begin{equation*}\tag{$*$} \int _{\mathbf{R} ^{N}} \Phi _{N}\left (\alpha \left ( \frac{\left |u(x)\right | }{\|\nabla u\| _{L^{N}(\mathbf{R} ^{N})}} \right )^{\frac{N}{N-1}}\right )\, dx \leq C_{\alpha } \frac {\|u\|_{L^{N}(\mathbf{R} ^{N})} ^{N}}{\|\nabla u\|_{L^{N}(\mathbf{R} ^{N})}^{N}} \end{equation*}](http://www.ams.org/proc/2000-128-07/S0002-9939-99-05180-1/gif-abstract/img10.gif)
for all . Here is defined by ![\begin{equation*}\Phi _{N}(\xi ) = \exp (\xi ) - \sum _{j=0}^{N-2} {\frac{1}{j!}}\xi ^{j}. \end{equation*}](http://www.ams.org/proc/2000-128-07/S0002-9939-99-05180-1/gif-abstract/img13.gif)
It is also shown that with is false, which is different from the usual Trudinger's inequalities in bounded domains. |