In geometry, Boy's surface is an immersion of the real projective plane in three-dimensional space. It was discovered in 1901 by the German mathematician Werner Boy, who had been tasked by his doctoral thesis advisor David Hilbert to prove that the projective plane could not be immersed in three-dimensional space.
Boy's surface was first parametrized explicitly by Bernard Morin in 1978.[1] Another parametrization was discovered by Rob Kusner and Robert Bryant.[2] Boy's surface is one of the two possible immersions of the real projective plane which have only a single triple point.[3]
Unlike the Roman surface and the cross-cap, it has no other singularities than self-intersections (that is, it has no pinch-points).