Euclidean geometry is the branch of mathematics describing shapes and the spatial relationships between objects in ...

Researchers have solved a long-standing problem in topology by helping classify four-dimensional shapes (4-manifolds) that ...

This article was originally published with the title “ Non-Euclidean Geometry before Euclid ” in Scientific American Magazine Vol. 221 No. 5 (November 1969), p. 87 doi:10.1038 ...