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Algèbres enveloppantes à homotopie près, homologies et cohomologies

Ridha Chatbouri (2011)

Annales de la faculté des sciences de Toulouse Mathématiques

On présente une définition et une construction unifée des homologies et cohomologies d’algèbres et de modules sur ces algèbres et de modules sur ces algèbres dans le cas d’algèbres associatives ou commutatives ou de Lie ou de Gertsenhaber. On sépare la construction linéaire des cogèbres ou bicogèbres qui traduisent les symétries des relations de définition de la structure de la partie structure qui apparaît ici comme une codérivation de degré 1 et de carré nul de la cogèbre ou de la bicogèbre.

Almost ff-universal and q-universal varieties of modular 0-lattices

V. Koubek, J. Sichler (2004)

Colloquium Mathematicae

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

Rüdiger Göbel, Saharon Shelah (1999)

Colloquium Mathematicae

Let R be a subring of the rationals. We want to investigate self splitting R-modules G, that is, such that E x t R ( G , G ) = 0 . 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...

An addendum and corrigendum to "Almost free splitters" (Colloq. Math. 81 (1999), 193-221)

Rüdiger Göbel, Saharon Shelah (2001)

Colloquium Mathematicae

Let R be a subring of the rational numbers ℚ. We recall from [3] that an R-module G is a splitter if E x t ¹ R ( G , G ) = 0 . 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)

Seytek Tabaldyev (2014)

Open Mathematics

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 .

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