Math 2.0

Linear and multilinear algebra; matrix theory Object

Matrix ring

Description

Let RR be a ring and let n≥1n \ge 1 be an integer. The matrix ring Mn(R)M_n(R) is the set of n×nn \times n matrices over RR, with matrix addition and matrix multiplication. It is a ring, with the zero matrix as zero and the identity matrix InI_n as unit. If RR is commutative, then Mn(R)M_n(R) is also an algebra over RR, with scalar multiplication.

Remarks

For n≥2n \ge 2 and R≠0R \ne 0, the ring Mn(R)M_n(R) is not commutative and has nonzero elements whose product is zero. The units of Mn(R)M_n(R) are the invertible matrices, and they form the general linear group. For a field FF, the ring Mn(F)M_n(F) is isomorphic to the ring of endomorphisms of FnF^n.

Where this leads

19 pages build on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Matrix_ring, lead section
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