Let $V$, $W$ be vector spaces over a field $F$ and $f : V \to W$ be a linear mapping. By LM#PROP-K (I), $\ker f$ is a subspace. The nullity of $f$ is the dimension of $\ker f$:
\[\null f = \dim \ker f.\]
Let $V$, $W$ be vector spaces over a field $F$ and $f : V \to W$ be a linear mapping. By LM#PROP-K (I), $\ker f$ is a subspace. The nullity of $f$ is the dimension of $\ker f$:
\[\null f = \dim \ker f.\]