A Bounded Below, Noncontractible, Acyclic Complex Of Projective Modules

exist over the cocommutative symmetric coalgebra of an infinite-dimensional vector space. [3/3 of https://t.co/k2CZDyCWEq]

are certain rings of infinite matrices with entries in the rings of commutative polynomials or formal power series in infinitely many variables. In the world of comodules or contramodules over coalgebras over fields, similar examples [2/3 of https://t.co/k

We construct examples of bounded below, noncontractible, acyclic complexes of finitely generated projective modules over some rings $S$, as well as bounded above, noncontractible, acyclic complexes of injective modules. The rings $S$ [1/3 of https://t.co/k

Leonid Positselski: A bounded below, noncontractible, acyclic complex of projective modules https://t.co/GTMe2149Fg https://t.co/lEI007koUZ