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