===== Boussinesq–Cerruti solution - point force at the origin of an infinite isotropic half-space =====
Another useful solution is that of a point force acting on the surface of an infinite half-space. It was derived by Boussinesq<ref>{{cite book |title=Application des potentiels à l'étude de l'équilibre et du mouvement des solides élastiques |last=Boussinesq |first=Joseph |author-link=Joseph Boussinesq |year=1885 |publisher=Gauthier-Villars |___location=Paris, France |url=http://name.umdl.umich.edu/ABV5032.0001.001 |archive-date=2024-09-03 |access-date=2007-12-19 |archive-url=https://web.archive.org/web/20240903234441/https://quod.lib.umich.edu/cgi/t/text/text-idx?c=umhistmath;idno=ABV5032.0001.001 |url-status=live }}</ref> for the normal force and Cerruti for the tangential force and a derivation is given in Landau & Lifshitz.<ref name="LL" />{{rp|§8}} In this case, the solution is again written as a Green's tensor which goes to zero at infinity, and the component of the stress tensor normal to the surface vanishes. This solution may be written in Cartesian coordinates as [recall: <math>a=(1-2\nu)</math> and <math>b=2(1-\nu)</math>, <math>\nu</math> = Poisson's ratio]:
