Let $F : R^k \to R^k$ be a smooth map whose Jacobian $J(F): R^k \to R$ vanishes on a discrete set $S$, so that if $O$ is the complement of $S$, then $f: O \to R^k$, the restriction of $F$, is a local diffeomorphism, and in particular there are only finitely many points $x$ inside the unit ball of $R^k$ such that $f(x) = 0$. What I would like to know is if there any a good algorithm for finding such points $x$. Of course, if $k=1$ this is easy, using the Intermediate Value Theorem; just partition the interval $[1,1]$ into a reasonably large number $N$ of subintervals of length $2/N$ and test on which subintervals $f$ changes sign, and then use bisection to locate a zero in those subintervals. If $k>1$ I suspect that some sort of application of Marching Cubes may work, but the usual search methods have not turned up anything.
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With a Lipschitz bound on the derivative, Newton's method gives an algorithm to efficiently approximate $F^{1}$. Hubbard's calculus textbook has a writeup using this perspective, viewing the result as a consequence of Kantorovich's Theorem. There's a fairly extensive analysis of the absolute error. 

