Fixed-degree polynomial limit (source code)

= Fixed-degree polynomial limit

If <polynomials> of degree at most $d$ converge at $d+1$ distinct points, their coefficients converge, by invertibility of the <Vandermonde matrix>. Their limit is a <polynomial> of degree at most $d$, and convergence is uniform on every compact subset of $\mathbb C$. Under convergence on compact sets, <Rouché's theorem> further locates a unique nearby zero for each simple root of the limit, for all sufficiently large indices. Finite initial polynomials need not have any root.