ThmDex – An index of mathematical definitions, results, and conjectures.
Vector space always has an inclusion-maximal linearly independent set
Formulation 0
Let $R$ be a D273: Division ring.
Let $V$ be a D29: Vector space over $R$ such that
(i) $\mathcal{L} : = \mathcal{L}_R(V)$ is the D2043: Set of linearly independent sets in $V$ over $R$
(ii) \begin{equation} \max(\mathcal{L}) : = \{ M \in \mathcal{L} \mid \forall \, L \in \mathcal{L} : L \subseteq M \} \end{equation}
Then \begin{equation} |\max(\mathcal{L})| \geq 1 \end{equation}
Proofs
Proof 0
Let $R$ be a D273: Division ring.
Let $V$ be a D29: Vector space over $R$ such that
(i) $\mathcal{L} : = \mathcal{L}_R(V)$ is the D2043: Set of linearly independent sets in $V$ over $R$
(ii) \begin{equation} \max(\mathcal{L}) : = \{ M \in \mathcal{L} \mid \forall \, L \in \mathcal{L} : L \subseteq M \} \end{equation}
This result is a particular case of R1406: Collection of sets ordered by inclusion contains a maximal element. $\square$