On the failure of Birkhoff's theorem for locally small based equational categories of algebras
On the Finistic dimension conjecture for Artinian Rings.
On the finiteness obstruction of certain periodic groups.
On the Freyd categories of an additive category.
On the functors Ext¹(E,F) for Fréchet spaces
On the geometric bar construction and the Brown representability theorem
On the Geometry of Associated Sheaves
On the geometry of computations
On the geometry of computations, II
On the geometry of intuitionistic S4 proofs.
On the Grothendieck topologies in the toposes of presheaves
On the homology of Lie groups made discrete.
On the homology of small categories and asynchronous transition systems.
On the homology theory of categories. I.
On the homology theory of categories. II.
On the Homology Theory of Central Group Extensions: I - The Commutator Map and Stem Extensions
On the homotopy theory of equivariant automorphism groups.
On the homotopy transfer of structures
The present article is devoted to the study of transfers for structures, their maps and homotopies, as developed in [7]. In particular, we supply the proofs of claims formulated therein and provide their extension by comparing them with the former approach based on the homological perturbation lemma.
On the injectivity of Boolean algebras
The functor taking global elements of Boolean algebras in the topos of sheaves on a complete Boolean algebra is shown to preserve and reflect injectivity as well as completeness. This is then used to derive a result of Bell on the Boolean Ultrafilter Theorem in -valued set theory and to prove that (i) the category of complete Boolean algebras and complete homomorphisms has no non-trivial injectives, and (ii) the category of frames has no absolute retracts.
On the integrality of the Witt polynomials.