817 - Algebra
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Contents
Groups
Theorems
Topics in Group Theory
Sylow Theory
Semi-Direct Product
Quotient Groups
Isomorphism Theorems
Rings
Definition: A ring is a set \(R\) with two binary operation \( +\) and \(\cdot\) satisfying:
- \( (R,+)\) is an abelian group (with identity 0)
- \( (R,\cdot) \) is a semigroup
- \(\cdot \) is distributive over \( + \) (on both sides)
Ideals
Named Rings
Euclidian Domains (EDs)
A Euclidean Domain (ED) is a domain \(R \) together with a function \(N: R \to \mathbb{Z}_{\geq 0} \) such that \(N(0)=0 \) and the following property holds: for any two elements \( a,b \in R \) with \(b\neq 0 \), there are elements \( q,r \in R\) such that \( a=qb+r \) and either \(r=0 \) or \(N(r)<N(b) \)