EN
We consider nonsingular polynomial maps F = (P,Q): ℝ² → ℝ² under the following regularity condition at infinity $(J_∞)$: There does not exist a sequence ${(p_k,q_k)} ⊂ ℂ²$ of complex singular points of F such that the imaginary parts $(ℑ(p_k),ℑ(q_k))$ tend to (0,0), the real parts $(ℜ(p_k),ℜ(q_k))$ tend to ∞ and $F(ℜ(p_k),ℜ(q_k))) → a ∈ ℝ²$. It is shown that F is a global diffeomorphism of ℝ² if it satisfies Condition $(J_∞)$ and if, in addition, the restriction of F to every real level set $P^{-1}(c)$ is proper for values of |c| large enough.