1
vote
2answers
68 views

Convergence over the $p$-adic numbers

so I'm a bit confused about convergence over the $p$-adic numbers - for example, I would argue that $\frac{1}{5^n}$ is not convergent over $\mathbb{Q}_5$ since $|\frac{1}{5^n}|_p = 5^n$ which is not ...
2
votes
3answers
512 views

p-adic expansion of a rational number

Studying $p$-adic numbers I encountered the following theorem: Given a eventually periodic sequence $(a_n)_{n=k}^{\infty}$ such that $0 \le a_n <p$, the sum \begin{equation*} ...
6
votes
4answers
327 views

Divergent series and $p$-adics

If we naïvely apply the formula $$\sum_0^\infty a^i = {1\over 1-a}$$ when $a=2$, we get the silly-seeming claim that $1+2+4+\ldots = -1$. But in the 2-adic integers, this formula is correct. Surely ...
7
votes
3answers
297 views

A property of some sequences of natural numbers (and their binary representation)

Let's consider a sequence of natural numbers $a_n$, represented in binary, with the following properties: $\forall n \in \mathbb{N}$ the number $a_n$ is represented with $n$ binary digits $\forall ...