On approximation of smooth submanifolds by nonsingular real algebraic subvarieties1
On approximation of smooth submanifolds by nonsingular real algebraic subvarieties1
Let M be a smooth submanifold of dimension m of a nonsingular real algebraic set X. If M can be approximated by nonsingular algebraic subsets of X, then the homology class in Hm(X,Z/2) represented by M is algebraic. The converse, investigated in this paper, is true only in some exceptional …