Algèbres graphiques (suites : Les bidules)
Algèbres graphiques (sur un concept de dimension dans les langages formels)
Algèbres non déterministiques et -catégories
Algébricité, monadicité, esquissabilité et non-algébricité
Almost abelian categories
Almost ff-universal and q-universal varieties of modular 0-lattices
A variety 𝕍 of algebras of a finite type is almost ff-universal if there is a finiteness-preserving faithful functor F: 𝔾 → 𝕍 from the category 𝔾 of all graphs and their compatible maps such that Fγ is nonconstant for every γ and every nonconstant homomorphism h: FG → FG' has the form h = Fγ for some γ: G → G'. A variety 𝕍 is Q-universal if its lattice of subquasivarieties has the lattice of subquasivarieties of any quasivariety of algebras of a finite type as the quotient of its sublattice....
Almost free splitters
Let R be a subring of the rationals. We want to investigate self splitting R-modules G, that is, such that . For simplicity we will call such modules splitters (see [10]). Also other names like stones are used (see a dictionary in Ringel’s paper [8]). Our investigation continues [5]. In [5] we answered an open problem by constructing a large class of splitters. Classical splitters are free modules and torsion-free, algebraically compact ones. In [5] we concentrated on splitters which are larger...
Amoeba relation and Galois-Tukey connections
An abstract characterization of the jet spaces
An abstract setting for homotopy pushouts and pullbacks
An action-free characterization of weak Hopf-Galois extensions.
An addendum and corrigendum to "Almost free splitters" (Colloq. Math. 81 (1999), 193-221)
Let R be a subring of the rational numbers ℚ. We recall from [3] that an R-module G is a splitter if . In this note we correct the statement of Main Theorem 1.5 in [3] and discuss the existence of non-free splitters of cardinality ℵ₁ under the negation of the special continuum hypothesis CH.
An additivity formula for the strict global dimension of C(Ω)
Let A be a unital strict Banach algebra, and let K + be the one-point compactification of a discrete topological space K. Denote by the weak tensor product of the algebra A and C(K +), the algebra of continuous functions on K +. We prove that if K has sufficiently large cardinality (depending on A), then the strict global dimension is equal to .
An algebraic description of locally multipresentable categories.
An anabelian definition of abelian homology
An Analogue of Stickelberger's Theorem for the Higher K-Groups.
An application of nonstandard analysis to category
An approach to a dual of regular closure operators
An axiomatic approach to homological dimension.
An elementary approach to some applications of nonstandard analysis