Polynomial Retracts and the Jacobian Conjecture
Polynomial Retracts and the Jacobian Conjecture
Let $K[x, y]$ be the polynomial algebra in two variables over a field $K$ of characteristic $0$. A subalgebra $R$ of $K[x, y]$ is called a retract if there is an idempotent homomorphism (a retraction, or projection) $\varphi : K[x, y] \to K[x, y]$ such that $\varphi (K[x, y]) = …