## Definition ## A __$\mathbb{Q}$-algebra__ is a [[Q-vector space|$\mathbb{Q}$-vector space]] $A$ with a [[bilinear function]] $(-)\cdot(-): A \times A \to A$ ## Examples ## * Every [[contractible type]] is a $\mathbb{Q}$-algebra. * The [[rational numbers]] are a $\mathbb{Q}$-algebra. ## See also ## * [[divisible group]] * [[Z-algebra]] * [[unital Q-algebra]] * [[algebra (module theory)]]