## Book Review: deMeyer and Ingraham's "Separable Algebras over Commutative Rings"

Let $R$ be a commutative ring. We say that an $R$-algebra $A$ is separable if it is projective as an $A\otimes_R A^{\rm op}$-module. Examples include full matrix rings over $R$, finite separable field extensions, and $\Z[\tfrac 12,i]$ as a $\Z[\tfrac 12]$-algebra. The 1970 classic Separable Algebras by deMeyer and Ingraham acquaints the reader with this […]