On stable hypersurfaces with vanishing scalar curvature

We will prove that there are no stable complete hypersurfaces of $mathbb {R}^4$ with zero scalar curvature, polynomial volume growth and such that $frac{(-K)}{H^3}ge c>0$ everywhere, for some constant $c>0$ , where K denotes the Gauss-Kronecker curvature and $H$ denotes the mean curvature of the immersion. Our second result is the Bernstein type one there is no entire graphs of $mathbb {R}^4$ with zero scalar curvature such that $frac{(-K)}{H^3}ge c>0$ everywhere. At last, it will be proved that, if there exists a stable hypersurface with zero scalar curvature and $frac{(-K)}{H^3}ge c>0$ everywhere, that is, with volume growth larger than polynomial growth of order four, then its tubular neighborhood is not embedded for suitable radius.