[[K-algebra]]
# Subalgebra

A **subalgebra** $W$ of a [[K-algebra|algebra]] $(V, \cdot)$ is a [[vector subspace]] $W \sube V$ that is closed under $(\cdot)$, #m/def/falg 
i.e. $W\cdot W \sube W$.

## Specifications

- [[Lie subalgebra]]
- [[Unital subalgebra]] also demands the identity be included

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#state/tidy | #lang/en | #SemBr