Mahler's theorem

In mathematics, Mahler's theorem, introduced by Kurt Mahler (1958), expresses any continuous p-adic function as an infinite series of certain special polynomials.

It is the p-adic counterpart to the Stone-Weierstrass theorem for continuous real-valued functions on a closed interval.

be the forward difference operator.

Then for any p-adic function

, Mahler's theorem states that

is continuous if and only if its Newton series converges everywhere to

th binomial coefficient polynomial.

th forward difference is computed by the binomial transform, so that

{\displaystyle (\Delta ^{n}f)(0)=\sum _{k=0}^{n}(-1)^{n-k}{\binom {n}{k}}f(k).}

is continuous if and only if the coefficients

It is remarkable that as weak an assumption as continuity is enough in the p-adic setting to establish convergence of Newton series.

By contrast, Newton series on the field of complex numbers are far more tightly constrained, and require Carlson's theorem to hold.