Proving GL(n) Center Diagonal Matrices

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In summary, the center of GL(n) is not the set of diagonal matrices. It is actually the set of all scalar matrices, where A is in the center if and only if A = c*I for some scalar c in the field F\{0}. It is easy to prove that ADA^-1 = D if D is diagonal, but if ABA^-1 = B is true, then B is not necessarily diagonal. One suggestion for solving problems like this is to consider simple cases, such as taking n = 2 and using elementary matrices.
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Jim Kata
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Is the center of GL(n) the set diagonal martices? It's easy to prove that ADA^-1 = D if D is diagonal, but if ABA^-1 = B is true that B is diagonal.
 
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no, the center is the set of all scalar matrices, ie, A is in the center iff A = c*I for some c in F\{0}

consider elementary matricesanother suggestion, when working on problems like this where you don't know what it is you want to prove, think simple, ie, take n = 2, and A = (1 0; 0 -1) which is diagonal, and B = (2 3; 1 1), then AB != BA, so A is not in the center but A is a diagonal matrix.
 
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FAQ: Proving GL(n) Center Diagonal Matrices

What is GL(n)?

GL(n) stands for the general linear group, which consists of all invertible n-by-n matrices. In other words, it is the group of all non-singular matrices of size n.

What are center diagonal matrices?

Center diagonal matrices are square matrices where all elements outside the main diagonal (the diagonal from the top left corner to the bottom right corner) are zero. The elements on the main diagonal can be any non-zero numbers.

How do you prove that all center diagonal matrices are in the center of GL(n)?

To prove that all center diagonal matrices are in the center of GL(n), we need to show that they commute with all other matrices in GL(n). This can be done by multiplying a center diagonal matrix with an arbitrary matrix in GL(n) and showing that the result is the same when the order of multiplication is reversed.

Why is proving that GL(n) center diagonal matrices are in the center important?

Proving that GL(n) center diagonal matrices are in the center is important because it helps us understand the structure of the general linear group. It also has applications in fields such as linear algebra, group theory, and physics.

Can you give an example of a center diagonal matrix in GL(n)?

Yes, an example of a center diagonal matrix in GL(n) is the identity matrix, where all elements on the main diagonal are 1 and all other elements are 0. This matrix commutes with all other matrices in GL(n) and is therefore in the center.

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