Linear transformation and Ker(T)

In summary, the speaker is asking for clarification on whether a linear transformation with a kernel consisting only of the zero vector will have a basis of dimension zero. They also ask about the relationship between injectivity and surjectivity in determining if a transformation is invertible. The expert responds that a subspace with only the zero vector has dimension zero and that injectivity does not guarantee surjectivity in determining invertibility.
  • #1
Benny
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Hi, suppose I have a linear transformation T and Ker(T) consists of only the zero vector. Then is it true that a basis for Ker(T) consists of no vectors and is of dimension zero? I would like these technicalities to be clarified. Any help would be good thanks.
 
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  • #2
Yes, the "subspace" consisting only of the 0 vector has dimension 0.
 
  • #3
Ok thanks HallsofIvy.

Just one more thing, if a transformation is injective then it is not necessarily onto? I ask this because I would like to know if in determining whether a transformation is invertible, if it is sufficient to look at whether or not it is injective.
 
  • #4
Just one more thing, if a transformation is injective then it is not necessarily onto?

Correct. It's very easy to find an example of an injection which is not surjective.

I ask this because I would like to know if in determining whether a transformation is invertible, if it is sufficient to look at whether or not it is injective.

Sometimes it is (such as when the transformation is between two spaces with the same (finite) dimension).
 
  • #5
Thanks for quick reply Muzza.
 

1. What is a linear transformation?

A linear transformation is a mathematical function that maps one vector space to another, while preserving the operations of vector addition and scalar multiplication. In simpler terms, it is a way to transform one set of vectors into another set of vectors using a set of rules.

2. What is the kernel of a linear transformation?

The kernel of a linear transformation, also known as the null space, is the set of all vectors in the domain that get mapped to the zero vector in the codomain. In other words, it is the set of all vectors that the linear transformation "ignores" or maps to the origin.

3. How do you find the kernel of a linear transformation?

To find the kernel of a linear transformation, you can set up a system of equations using the transformation's matrix representation and solve for the variables. The solutions to the system of equations will form the basis for the kernel.

4. What is the relationship between the kernel and the range of a linear transformation?

The kernel and range of a linear transformation are complementary subspaces. This means that the dimensions of the kernel and range add up to the total dimension of the vector space. Additionally, any vector in the range can be written as the sum of a vector in the kernel and a vector in the range.

5. Why is the kernel of a linear transformation important?

The kernel of a linear transformation is important because it allows us to understand the behavior of the transformation. It helps us determine if the transformation is one-to-one (injective) or onto (surjective), and it provides a way to find solutions to systems of linear equations. Additionally, the kernel is useful in applications such as image and signal processing, where it can help identify patterns and reduce noise.

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