منابع مشابه
Separable bimodules and approximation
Using approximations, we give several characterizations of separability of bimodules. We also discuss how separability properties can be used to transfer some representation theoretic properties from one ring to another one: contravariant finiteness of the subcategory of (finitely generated) left modules with finite projective dimension, finitistic dimension, finite representation type, Ausland...
متن کاملBimodules and Abelian Surfaces
Introduction In a manuscript on mod representations attached to modular forms [26], the author introduced an exact sequence relating the mod p reduction of certain Shimura curves and the mod q reduction of corresponding classical modular curves. Here p and q are distinct primes. More precisely, fix a maximal order O in a quaternion algebra of discriminant pq over Q. Let M be a positive integer ...
متن کاملMonads of Effective Descent Type and Comonadicity
We show, for an arbitrary adjunction F U : B → A with B Cauchy complete, that the functor F is comonadic if and only if the monad T on A induced by the adjunction is of effective descent type, meaning that the free T-algebra functor F : A → AT is comonadic. This result is applied to several situations: In Section 4 to give a sufficient condition for an exponential functor on a cartesian closed ...
متن کاملA-H-bimodules and equivalences
In [6, Theorem 2.2] Doi gave a Hopf-algebraic proof of a generalization of Oberst’s theorem on affine quotients of affine schemes. He considered a commutative Hopf algebra H over a field, coacting on a commutative H-comodule algebra A. If AcoH denotes the subalgebra of coinvariant elements of A and β : A ⊗AcoH A −→ A ⊗H the canonical map, he proved that the following are equivalent: (a) AcoH ⊂ ...
متن کاملSpectral synthesis and masa-bimodules
The interaction between Harmonic Analysis and Operator Theory has been fruitful. In [1] Arveson related results in the Theory of Operator Algebras to such in Spectral Synthesis. He defined synthesis for subspace lattices and proved that certain classes of lattices are synthetic. The main result in this note is a generalization of a result of Arveson for the case of subspace maps. In order to de...
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ژورنال
عنوان ژورنال: Journal of Algebra
سال: 2007
ISSN: 0021-8693
DOI: 10.1016/j.jalgebra.2007.03.025