## Definition ## A __$\mathbb{Q}$-algebra__ is a [[ring]] $A$ with a [[ring homomorphism]] $h: \mathbb{Q} \to A$ ## Examples ## * Every [[contractible type]] is a $\mathbb{Q}$-algebra. * The [[rational numbers]] are a $\mathbb{Q}$-algebra. ## See also ## * [[ring]] category: not redirected to nlab yet