# Tag Archives: spectral sequences

## Wild Spectral Sequences Ep. 4: Schanuel's Lemma

It's time for another installment of Wild Spectral Sequences! We shall start our investigations with a classic theorem useful in many applications of homological algebra called Schanuel's lemma, named after Stephen Hoel Schanuel who first proved it. Consider for a ring $R$ the category of left $R$-modules, and let $A$ be any […]