Bernard Morin (French: [mɔʁɛ̃]; 3 March 1931 in Shanghai, China – 12 March 2018)^[1] 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.^[2] He received his Ph.D. in 1972 from the Centre National de la Recherche Scientifique.^[3][2]

Morin was a member of the group that first exhibited an eversion of the sphere,^[4] i.e., a homotopy 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.

Morin discovered the first parametrization of Boy's surface (earlier used as a half-way model), in 1978. His graduate student François Apéry, in 1986, discovered another parametrization of Boy's surface, which conforms to the general method for parametrizing non-orientable surfaces.^[5]

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

Morin's surface.

• Blind mathematicians: Leonhard Euler, Nicholas Saunderson, Lev Pontryagin, Louis Antoine

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

• Photos of Morin Archived 2019-04-20 at the Wayback Machine with stereolithography models of sphere eversion.
• The World of Blind Mathematicians, PDF file at the American Mathematical Society's website.