Uniformly Hyperarchimedean Lattice-Ordered Groups

An abelian ?-group with strong unit (\(\user1{\mathcal{L}}_1 \)-object) G is hyperarchimedean (HA) iff G?≤?C(YG) (the ?-group of real continuous functions on the maximal ideal space, YG) with λ(g)?=?inf{?∣?g(x)?∣?≠?0}?>?0 for each 0?≠?g?∈?G. In case inf{λ(g):0?≠?g?∈?G}?>?0, we call G uniformly hyperarchimedean (UHA). This paper: examines the structure of the UHA groups in detail; shows that UHA solves the problem: when is an \(\user1{\mathcal{L}}_1 \)-product HA?; describes completely the \(\user1{\mathcal{L}}_1 \)???HSP-classes which are contained in HA. Final remarks detail the connection with MV-algebras.     

Duality theorem for L-R crossed coproducts

In this paper, the notion of L-R crossed coproduct is introduced as a unified approach for smash coproducts, crossed coproducts and L-R smash coproducts of Hopf algebras. A duality theorem for L-R crossed coproduct is proved.     

扭曲Smash余积的辫Monoidal范畴

主要讨论扭曲Smash余积余模范畴c×Hll,得到c×Hll是辫monoidal范畴的一个充要条件.     

The global dimensions of crossed products and crossed coproducts

In this paper, we show that if H is a finite-dimensional Hopf algebra such that H and H^＊ are semisimple, then gl.dim（A#σH）=gl.dim（A）, where a is a convolution invertible cocycle. We also discuss the relationship of global dimensions between the crossed product A^#σH and the algebra A, where A is coacted by H. Dually, we give a sufficient condition for a finite dimensional coalgebra C and a finite dimensional semisimple Hopf algebra H such that gl.dim（C α H）=gl.dim（C）.     

On skew field coproducts with a finite extension

It is shown that the field coproduct of any skew fieldE with a binomial (commutative) field extensionF/k overk can be expressed as a cyclic extension of a skew fieldK (theE-socle), itself the field coproduct of [F:k] copies ofE overk. Qua vector space the coproduct may also be expressed as a tensor product ofE andK overk. To the memory of Shimshon Amitsur     

Tame parts of free summands in coproducts of Priestley spaces

It is well known that a sum (coproduct) of a family of Priestley spaces is a compactification of their disjoint union, and that this compactification in turn can be organized into a union of pairwise disjoint order independent closed subspaces Xu, indexed by the ultrafilters u on the index set I. The nature of those subspaces Xu indexed by the free ultrafilters u is not yet fully understood.In this article we study a certain dense subset satisfying exactly those sentences in the first-order theory of partial orders which are satisfied by almost all of the Xi's. As an application we present a complete analysis of the coproduct of an increasing family of finite chains, in a sense the first non-trivial case which is not a ?ech-Stone compactification of the disjoint union I_?Xi. In this case, all the Xu's with u free turn out to be isomorphic under the Continuum Hypothesis.     

On the existence of coproducts in the category of noncommutative algebras

The weakly multiplicative bilinear maps among R-algebras are introduced and the corresponding to them category of pointed algebras is defined. By the resolution of the respective universal problem, a new tensor product of two R-algebras is realized and its connection with the usual one is pointed out. Furthermore, after establishing the existence of an infinite (new) tensor product algebra, as a special colimit, it is shown that coproducts there always exist in the category Al of noncommutative (associative, unitary) R-algebras. Certain canonical decompositions of a given algebra in some particular cases are also investigated.     

Semidirect products of weak multiplier Hopf algebras: Smash products and smash coproducts

In this paper, we will develop the smash product of weak multiplier Hopf algebras unifying the cases of Hopf algebras, weak Hopf algebras and multiplier Hopf algebras. We will show that the smash product R#A has a regular weak multiplier Hopf algebra structure if R and A are regular weak multiplier Hopf algebras. We shall investigate integrals on R#A. We also consider the result in the ?-situation and new examples. Dually, we consider the smash coproduct of weak multiplier Hopf algebras under an appropriate form and integrals on the smash coproduct and we obtain results in the ?-situation.     

Loop coproducts in string topology and triviality of higher genus TQFT operations

Cohen and Godin constructed a positive boundary topological quantum field theory (TQFT) structure on the homology of free loop spaces of oriented closed smooth manifolds by associating certain operations called string operations to orientable surfaces with parametrized boundaries. We show that all TQFT string operations associated to surfaces of genus at least one vanish identically. This is a simple consequence of properties of the loop coproduct which will be discussed in detail. One interesting property is that the loop coproduct is nontrivial only on the degree d homology group of the connected component of LM consisting of contractible loops, where d=dimM, with values in the degree 0 homology group of constant loops. Thus the loop coproduct behaves in a dramatically simpler way than the loop product.