Kernel of linear transformation is subspace of domain

Dependencies:

  1. Linear transformation
  2. Condition for being a subspace

Let $T: U \mapsto V$ be a linear transformation. Let $K = \{u \in U: T(u) = 0\}$. $K$ is called the kernel of $T$. Then $K$ is a subspace of $U$.

Proof

\[ x, y \in K \implies (T(x) = 0 \wedge T(y) = 0) \implies T(x+y) = T(x) + T(y) = 0 \implies x + y \in K \]

\[ x \in K \implies T(x) = 0 \implies T(cx) = cT(x) = 0 \implies cx \in K \]

Therefore, $K$ is a subspace of $U$.

Dependency for:

  1. Basis of range of linear transformation

Info:

Transitive dependencies:

  1. Group
  2. Identity of a group is unique
  3. Subgroup
  4. Inverse of a group element is unique
  5. Conditions for a subset to be a subgroup
  6. Condition for a subset to be a subgroup
  7. Ring
  8. Field
  9. Vector Space
  10. Zeros in vector space
  11. Negation in vector space
  12. Condition for being a subspace
  13. Linear transformation