Preradicals
Preradicals and change of rings
Preserving homology.
Projective abelian Hopf algebras over a field [Book]
Propriétés du groupe tannakien des structures de Hodge -adiques et torseur entre cohomologies cristalline et étale
On donne des propriétés de la catégorie tannakienne des modules de Dieudonné filtrés sur un corps -adique (ces modules de Dieudonné jouent en -adique un rôle analogue aux structures de Hodge complexes). On prouve l’existence d’un foncteur fibre sur et la simple connexité du groupe associé. Ceci permet de montrer, sous la conjecture de Fontaine : “faiblement admissible entraîne admissible”, une conjecture de Rapoport et Zink décrivant le torseur entre cohomologie cristalline et étale, et de prouver...
Protolocalisations of exact Mal'cev categories.
Pseudohereditary and pseudocohereditary preradicals
modules and rings
Quadratische Formen in additiven Kategorien
Quasi-abelian categories and sheaves
Quasi-radicals and Radicals in Categories
Quasi-tilted algebras of canonical type
Quelques remarques sur les opérateurs et les q-algèbres de Banach.
Quotient Banach spaces
Quotient Banach spaces; Multilinear theory
Quotients, fractions, symmetrizations
Radicals which define factorization systems
A method due to Fay and Walls for associating a factorization system with a radical is examined for associative rings. It is shown that a factorization system results if and only if the radical is strict and supernilpotent. For groups and non-associative rings, no radical defines a factorization system.
Rank additivity for quasi-tilted algebras of canonical type
Given the category of coherent sheaves over a weighted projective line (of any representation type), the endomorphism ring of an arbitrary tilting sheaf - which is by definition an almost concealed canonical algebra - is shown to satisfy a rank additivity property (Theorem 3.2). Moreover, this property extends to the representationinfinite quasi-tilted algebras of canonical type (Theorem 4.2). Finally, it is demonstrated that rank additivity does not generalize to the case of tilting complexes...
Realization of long exact sequences of abelian groups.
Given a long exact sequence of abelian groupsL: ... → Li-1 →ξi-1 Li →ξi Li+1 → ...a short exact sequence of complexes of free abelian groups is constructed whose cohomology long exact sequence is precisely L. In this sense, L is realized. Two techniques which are introduced to reduce or replace lengthy diagram chasing arguments may be of interest to some readers. One is an arithmetic of bicartesian squares; the other is the use of the fact that categories of morphisms of abelian categories...
Refining thick subcategory theorems
We use a K-theory recipe of Thomason to obtain classifications of triangulated subcategories via refining some standard thick subcategory theorems. We apply this recipe to the full subcategories of finite objects in the derived categories of rings and the stable homotopy category of spectra. This gives, in the derived categories, a complete classification of the triangulated subcategories of perfect complexes over some commutative rings. In the stable homotopy category of spectra we obtain only...