Every nxn matrix can be written as a linear combination of matrices in GL(n,F)

In summary, the statement is asking to prove that every nxn matrix can be written as a linear combination of matrices in GL(n,F), where GL(n,F) is the set of all nxn invertible matrices over the field F with the operation of matrix multiplication. One approach to proving this is to use the fact that all matrices in GL(n,F) have linearly independent columns and rows, which could potentially provide a basis for M_{nxn}(F), the set of all nxn matrices with dimension n^2. However, it is uncertain if this approach is valid.
  • #1
fishshoe
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Homework Statement


Prove: Every nxn matrix can be written as a linear combination of matrices in GL(n,F).


Homework Equations


GL(n,F) = the set of all nxn invertible matrices over the field F together with the operation of matrix multiplication.


The Attempt at a Solution


I know all matrices in GL(n,F) are invertible and hence have linearly independent columns and rows. I was thinking perhaps there is something about the joint bases for the n-dimensional column and row spaces, respectively, that could provide a basis for M_{nxn}(F), which has dimension of n^2. But I'm not really sure if that works.
 
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  • #2
Okay, I figured it out. Nevermind (although once a post gets buried two screens back, it's not likely to be answered anyway, even if it has zero replies...).
 

Related to Every nxn matrix can be written as a linear combination of matrices in GL(n,F)

1. What is GL(n,F)?

GL(n,F) refers to the general linear group, which is the set of all invertible n x n matrices with entries from the field F. In other words, it is the group of all matrices that have a determinant that is not equal to zero.

2. What is a linear combination?

A linear combination is a mathematical expression in which a set of elements (in this case, matrices) are multiplied by coefficients and added together. For example, the linear combination aA + bB, where A and B are matrices and a and b are coefficients, involves multiplying A by a and B by b, and then adding the results together.

3. How can an nxn matrix be written as a linear combination of matrices in GL(n,F)?

This can be done by using the properties of matrix multiplication and linear combinations. Since GL(n,F) contains all invertible n x n matrices, any nxn matrix can be written as a product of these matrices. By then expressing each of these matrices as a linear combination of matrices in GL(n,F), we can ultimately write the original nxn matrix as a linear combination of matrices in GL(n,F).

4. Why is this property important?

This property is important because it allows us to represent any nxn matrix in terms of a finite set of matrices from GL(n,F). This can be useful in various mathematical and scientific applications, such as solving systems of linear equations, performing matrix manipulations, and representing transformations.

5. Are there any exceptions to this property?

Yes, there are a few exceptions to this property. For example, it does not hold for matrices with entries from a finite field, as the inverse of a matrix in GL(n,F) may not be in the same field. It also does not hold for matrices with entries from a non-commutative field, as the order of multiplication matters in this case. Additionally, it may not hold for matrices with entries from a non-associative field, as the grouping of operations may affect the result.

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