p-Adic Numbers and Their Role
Algebraic Geometry•January 1, 2025
<p>The p-adic numbers form an extension of the rational numbers that are used to study problems in number theory and algebraic geometry. In this post, we will explore the p-adic numbers and their significance in modern algebraic geometry.</p>
<h3 id="what-are-p-adic-numbers">What are p-Adic Numbers?</h3>
<p>The p-adic numbers, denoted ( \mathbb{Q}_p ), are a system of numbers that extend the rational numbers by introducing a new topology based on the prime ( p ). They are used in the study of Diophantine equations, modular forms, and various other topics in number theory.</p>
<p>A number ( x \in \mathbb{Q}_p ) is represented as a series expansion:</p>
<p>$$<br>
x = a_0 + a_1 p + a_2 p^2 + \cdots<br>
$$</p>
<p>where the coefficients ( a_i ) are integers modulo ( p ).</p>
<h3 id="applications-of-p-adic-numbers">Applications of p-Adic Numbers</h3>
<p>p-Adic numbers are particularly useful in algebraic geometry for studying schemes and varieties over finite fields. They provide insight into the properties of algebraic structures, and they are widely used in the study of rational points on algebraic curves.</p>