Number Theory, sometimes called Elementary Number Theory, is a course that undergraduate students take at a college or university. This course is concerned with the study of the integers and often serves an additional purpose –an introduction to writing mathematical proofs. Topics include an in-depth analysis of mathematical induction and divisibility. Following this, the Euclidean algorithm and the Fundamental Theorem of Arithmetic are essential. After that, students will often learn linear congruence equations and systems of linear congruence equations. Special theorems on congruence such as Fermat’s and Euler’s theorem are of significant interest as they are useful, especially in computer science.
Okay, so you understand how to check if a quadratic congruence is solvable, but how do you find the solutions? In this article, I cover the Tonelli-Shanks algorithm by working through several examples. I also give a complete solution to a general quadratic congruence equation.
In this article, I cover topics related to solving quadratic congruences. In particular, I explain quadratic residues and the Legendre symbol in detail.
Many people have celebrated Euler’s Theorem, but its proof is much less traveled. In this article, I discuss many properties of Euler’s Totient function and reduced residue systems. As a result, the proof of Euler’s Theorem is more accessible. I also work through several examples of using Euler’s Theorem.
Maybe you have heard of Wilson’s Theorem? But did you know that’s is converse also holds. In this article, I prove both Wilson’s Theorem, its converse, and Fermat’s Theorem. Then you will also see many examples using Fermat’s theorem.
This definitive guide covers proofs, examples, algorithms, applications, and the Chinese Remainder Theorem history. It also includes links to additional resources such as online articles, courses, books, and tutors to help students learn from various sources. Professionals can also use these resources to increase their knowledge of the field or help structure courses for their students.
So you probably know a divisibility test for 2, 3, and 5. But what about 7, 11, 13, or even larger primes? In this article, I go over divisibility tests. Including how to create your own. I also discuss the Days of the Week problem, where you are to determine the day of the week from a given date very quickly.
The idea behind solving polynomial congruence equations is that we can reduce a congruence equation to an equivalent system of congruence equations using prime factorization. We then 1) solve each equation modulo a prime number (by brute force), 2) use Hensel’s Lifting theorem, and then 3) piece together the solutions using the Chinese Remainder Theorem. We provide several nontrivial examples many of which are workable by hand.
In this article, you will learn what linear congruences are and when they are solvable. How to solve them will also be covered in detail. I discuss an ad hoc method, using the Euclidean algorithm, and using the inverse of an integer.
In this article, I discuss modular congruence. I demonstrate the congruence is an equivalence relation, and I prove several lemmas concerning the basic properties of congruence. Towards the end, I go over modular arithmetic and its properties.
In this article, I discuss what Diophantine Equations are and the difficulting of solving them. Then, I detail how to solve two-variable linear diophantine equations. Towards the end, I solve a multi-variable linear Diophantine equation concerning pennies, dimes, and quarters.
