Abstract:
Examples of smooth fourth-degree hypersurfaces which are unirational over an algebraically nonclosed field $\Bbbk$ and contain no straight lines defined over $Bbbk$ are given. A method for proving the unirationality of quartics is suggested, which, unlike other methods, does not use linear spaces contained in the quartics.
Keywords:unirational quartic, quartic over an algebraically nonclosed field, unirational variety, irreducible hypersurface, Plucker embedding, birational projection.