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2. The universal mapping property

Proposition. If $ F $ is free in $ V $ on $ g _ 1,\dots, g _ n $ and $ A $ is any algebra in $ V $ and $ a _ 1,\dots, a _ n
\in A $, then there is a unique homomorphism $ \phi:F \rightarrow A $ with $ f(g _ {i}) = a _ i $ for each $ i $. (In other words, you can aim the generators of $ F $ at any elements of any algebra in $ V $ and find a homomorphism that takes the generators there.)



Corollary 1. Up to isomorphism, there is only one free algebra in $ V $ on $ n $ generators.

Let us call this algebra $ F _ V (n) $.



Corollary 2. Every $ n $-generated algebra of $ V $ is a homomorphic image of $ F _ V (n) $.



Corollary 3. If $ F _ V (n) $ is finite, then it is the largest $ n $-generated algebra in $ V $, and the only one of its size (up to isomorphism).



Kirby A. Baker 2003-02-18