Razar, M. Israel J. Math. (1979) 32: 97. doi:10.1007/BF02764906
It has been long conjectured that ifn polynomialsf1, …,fn inn variables have a (non-zero) constant Jacobian determinant then every polynomial can be expressed as a polynomial inf1, …,fn. In this paper, various extra assumptions (particularly whenn=2) are shown to imply the conclusion. These conditions are discussed algebraically and geometrically.