Linear Algebra Rank of a Matrix Problem

In summary, the rank of a matrix is the maximum number of linearly independent rows or columns in the matrix. It can be determined by performing row operations and finding the number of non-zero rows in the reduced row echelon form. A matrix can have a rank of 0 if all of its rows and columns are linearly dependent. The rank of a matrix tells us about its linear independence, dimensionality, and solutions to linear systems of equations. The rank also affects the invertibility of a matrix, with a square matrix being invertible if its rank is equal to its size.
  • #1
Heeyeyey
2
0
Let A be a n x n matrix with complex elements. Prove that the a(k) array, with k ∈ ℕ, where a(k) = rank(A^(k + 1)) - rank(A^k), is monotonically increasing.

Thank you! :)
 
Physics news on Phys.org
  • #2
This follows from $\operatorname {rank} (AB)\leq \min(\operatorname {rank} (A),\operatorname {rank} (B))$, if by "increasing" you mean "not decreasing".
 
  • #3
Finally solved it using the Frobenius Inequality for the rank of a matrix. Thank you anyway!
 

1. What is the definition of rank in linear algebra?

The rank of a matrix is the maximum number of linearly independent rows or columns in the matrix. In other words, it is the number of dimensions in the output of a matrix transformation.

2. How is the rank of a matrix calculated?

The rank of a matrix can be calculated by performing row reduction (Gaussian elimination) on the matrix and counting the number of non-zero rows or columns in the reduced matrix.

3. What is the significance of the rank of a matrix?

The rank of a matrix is important because it gives information about the dimension of the vector space spanned by the columns or rows of the matrix. It also determines whether a system of linear equations has a unique solution, no solution, or infinitely many solutions.

4. Can the rank of a matrix change?

No, the rank of a matrix is a fundamental property of the matrix and does not change. However, the rank of a matrix can be affected by elementary row operations, such as multiplying a row by a non-zero scalar or swapping two rows.

5. How is the rank of a matrix related to its determinant?

The rank of a matrix is related to its determinant in that a matrix is invertible (has a non-zero determinant) if and only if its rank is equal to the number of rows or columns in the matrix. In other words, a matrix is invertible if and only if it has full rank.

Similar threads

  • Linear and Abstract Algebra
Replies
4
Views
886
  • Linear and Abstract Algebra
Replies
19
Views
2K
  • Linear and Abstract Algebra
Replies
7
Views
1K
  • Linear and Abstract Algebra
Replies
3
Views
1K
  • Linear and Abstract Algebra
Replies
9
Views
4K
Replies
4
Views
1K
  • Linear and Abstract Algebra
Replies
19
Views
1K
  • Linear and Abstract Algebra
Replies
8
Views
1K
  • Linear and Abstract Algebra
Replies
15
Views
1K
  • Linear and Abstract Algebra
Replies
5
Views
1K
Back
Top