Archive for february, 2010

Inequalities.

tuesday, february 9th, 2010

This post shows a diagram, listing a lot of inequalities and showing implications between them.

How to Compute the 5-adic Expansion of 1/2; or: Hensel’s Lemma and (Non-Analytic) Newton Iteration.

saturday, february 6th, 2010

In this post, we consider the quest of computing the 5-adic expansion of 1/2. We begin with introducing p-adic integers and numbers, and discussing when certain polynomials with coefficients in the integers have zeroes in the p-adic integers. This question is closely related to Hensel’s lemma, which can be proven using an algebraic version of Newton’s iteration. We use this to compute approximations of rational numbers in the p-adics, and consider which p-adic numers have an eventually periodic expansion.