Jordan Forms, Nullity and Minimal Polynomials

In summary, the problem asks to find the possible Jordan forms and minimal polynomials for a matrix B, given that the nullity of (B-5I) is 2 and the nullity of (B-5I)^2 is 5. The characteristic polynomial of B is (λ-5)^12. The possible Jordan forms are Jn1(5) or ... or Jni(5), but the method for finding these forms and corresponding minimal polynomials is unclear. The minimal polynomial of a matrix represents the smallest polynomial that the matrix satisfies, and it is closely related to the matrix's eigenvectors.
  • #1
shaon0
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Homework Statement


Nullity(B-5I)=2 and Nullity(B-5I)^2=5
Characteristic poly is: (λ-5)^12
Find the possible jordan forms of B and the minimal polynomials for each of these JFs.

The Attempt at a Solution


JFs: Jn1(5) or ... or Jni(5).
Not sure how to find these jordan forms and minimal polynomials.
 
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  • #2
shaon0 said:

Homework Statement


Nullity(B-5I)=2 and Nullity(B-5I)^2=5
Characteristic poly is: (λ-5)^12
Find the possible jordan forms of B and the minimal polynomials for each of these JFs.

The Attempt at a Solution


JFs: Jn1(5) or ... or Jni(5).
Not sure how to find these jordan forms and minimal polynomials.

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  • #3
What does "minimal polynomial" for a matrix mean? What do you know about the relation between the minimal polynomial of a matrix and its eigenvectors?
 

FAQ: Jordan Forms, Nullity and Minimal Polynomials

What is a Jordan form?

A Jordan form is a way of representing a square matrix by breaking it down into a block diagonal form consisting of Jordan blocks. These blocks are square matrices with a constant value along the main diagonal and ones on the superdiagonal.

What is the nullity of a matrix?

The nullity of a matrix is the dimension of the null space, which is the set of all solutions to the equation Ax = 0 where A is the matrix. In other words, it is the number of linearly independent columns or rows in the matrix that result in the zero vector.

How is the minimal polynomial related to Jordan forms?

The minimal polynomial of a matrix is the smallest degree monic polynomial that, when evaluated at the matrix, results in the zero matrix. The degree of the minimal polynomial is also equal to the size of the largest Jordan block in the Jordan form of the matrix.

Can a matrix have multiple Jordan forms?

Yes, a matrix can have multiple Jordan forms depending on the choice of basis. However, all Jordan forms for a given matrix will have the same set of eigenvalues and their multiplicities will remain the same.

How do you calculate the Jordan form of a matrix?

The Jordan form of a matrix can be calculated by first finding the eigenvalues and their corresponding eigenvectors. Then, the eigenvectors are used to construct the Jordan blocks and these blocks are arranged in a block diagonal form to form the Jordan form of the matrix.

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