Bernard Morin

Bernard Morin ([mɔʁɛ̃]; 3 March 1931 in Shanghai, China – 12 March 2018) was a French mathematician, specifically a topologist.

Morin lost his sight at the age of six due to glaucoma, but his blindness did not prevent him from having a successful career in mathematics. He received his Ph.D. in 1972 from the Centre National de la Recherche Scientifique.

Morin was a member of the group that first exhibited an eversion of the sphere, i.e. a homotopy (topological metamorphosis) which starts with a sphere and ends with the same sphere but turned inside-out. He also discovered the Morin surface, which is a half-way model for the sphere eversion, and used it to prove a lower bound on the number of steps needed to turn a sphere inside out.

He discovered the first parametrization of Boy's surface (earlier used as a half-way model) in 1978.His graduate student François Apéry later discovered (in 1986) another parametrization of Boy's surface, which conforms to the general method for parametrizing non-orientable surfaces.

Morin worked at the Institute for Advanced Study in Princeton.Most of his career, though, he spent at the University of Strasbourg.

• George K. Francis & Bernard Morin (1980) "Arnold Shapiro’s Eversion of the Sphere", Mathematical Intelligencer 2(4):200–3.