On Mappings of Finite Codimension
Andrew Du Plessis · Proceedings of the London Mathematical Society · 1985
Elementary considerations lead quickly to abstract conditions on the pair (dimN, dimP) under which the set of C°°-stable maps N- * P is not dense in C°°(N, P), and indeed to abstract conditions under which there are no C°°-stable maps in a given homotopy class of maps N-> P. Moreover, special cases yield very explicit