Representationsmatriserna

Representationsmatriserna, often translated as "representation matrices" or "matrix representations" in English, are a fundamental concept in abstract algebra and group theory. They provide a way to study abstract groups by mapping their elements to invertible matrices. This allows the use of the well-developed machinery of linear algebra to understand group properties.

A representation of a group G is a homomorphism from G to a group of invertible matrices, typically under matrix multiplication. If the matrices are over a field like real numbers or complex numbers, this is called a matrix representation. The set of all n x n invertible matrices over a field forms a general linear group, denoted GL(n, F). Thus, a representation is a map ρ: G → GL(n, F).

The dimension of the representation is the size n of the matrices. A representation is called faithful if the homomorphism is injective, meaning distinct group elements are mapped to distinct matrices. Reducible representations can be decomposed into smaller, irreducible representations, while irreducible representations cannot be further decomposed. Understanding these irreducible representations is crucial as they form the building blocks of all other representations of a group.

Representationsmatriserna are vital tools for studying symmetries in physics and chemistry, analyzing discrete structures, and solving problems in various branches of mathematics. They offer a concrete and calculable way to explore the abstract structure of groups.