Additivity of homological dimensions for a class of Banach algebras

Let Ω be a metrizable compact space. Suppose that its derived set of some finite order is empty. Let B be a unital Banach algebra, and let $\widehat \otimes $ stand for the projective tensor product. We prove the additivity formulas dg C(Ω)B $\widehat \otimes $ =dgB and db C(Ω) $\widehat \otimes $ B=dbC(Ω)+dbB for the global homological dimension and the homological bidimension. Thus these formulas are true for a new class of commutative Banach algebras in addition to those considered earlier by Selivanov.     

On (co)homology locally connected spaces

We prove that there exists a cohomology locally connected compact metrizable space which is not homology locally connected. In the category of compact Hausdorff spaces a similar result was proved earlier by G.E. Bredon.     

Actions of totally disconnected groups and equivariant singular homology

We study equivariant singular homology in the case of actions of totally disconnected locally compact groups on topological spaces. Theorem A says that if G is a totally disconnected locally compact group and X is a G-space, then any short exact sequence of covariant coefficient systems for G induces a long exact sequence of corresponding equivariant singular homology groups of the G-space X. In particular we consider the case where G is a totally disconnected compact group, i.e., a profinite group, and G acts freely on X. Of special interest is the case where G is a p-adic group, p a prime. The conjecture that no p-adic group, p a prime, can act effectively on a connected topological manifold, is namely known to be equivalent to the famous Hilbert-Smith conjecture. The Hilbert-Smith conjecture is the statement that, if a locally compact group G acts effectively on a connected topological manifold M, then G is a Lie group.     

On infinite dimensional quadratic Volterra operators

In this paper we study a class of quadratic operators named by Volterra operators on infinite dimensional space. We prove that such operators have infinitely many fixed points and the set of Volterra operators forms a convex compact set. In addition, it is described its extreme points. Besides, we study certain limit behaviors of such operators and give some more examples of Volterra operators for which their trajectories do not converge. Finally, we define a compatible sequence of finite dimensional Volterra operators and prove that any power of this sequence converges in weak topology.     

Flabby sheaves of chains for singular homology

Iterating the barycentric subdivision operator in a singular complex, we construct flabby sheaves of chains for singular homology. Translated fromMatematicheskie Zametki, Vol. 65, No. 3, pp. 396–401, March, 1999.     

Local minima of lattices and vertices of Klein polyhedra

We prove that each vertex of a Klein polyhedron of a lattice is a local minimum.     

Weaker connected and weaker nowhere locally compact topologies for metrizable and similar spaces

We prove that any metrizable non-compact space has a weaker metrizable nowhere locally compact topology. As a consequence, any metrizable non-compact space has a weaker Hausdorff connected topology. The same is established for any Hausdorff space X with a σ-locally finite base whose weight w(X) is a successor cardinal.     

On the equivalence of multiplicative structures in floer homology and quantum homology

In this paper, we will prove that Floer homology equipped with either the intrinsic or exterior product is isomorphic to quantum homology as a ring. We will also prove that GW-invariants in Floer homology and quantum homology are equivalent.     

Resolutions for free partially commutative monoids

We construct a free resolution for a free partially commutative monoid and, using this resolution, estimate the homological dimension of the monoid.     

On knot Floer homology and lens space surgeries

In an earlier paper, we used the absolute grading on Heegaard Floer homology HF⁺ to give restrictions on knots in S³ which admit lens space surgeries. The aim of the present article is to exhibit stronger restrictions on such knots, arising from knot Floer homology. One consequence is that the non-zero coefficients of the Alexander polynomial of such a knot are ±1. This information can in turn be used to prove that certain lens spaces are not obtained as integral surgeries on knots. In fact, combining our results with constructions of Berge, we classify lens spaces L(p,q) which arise as integral surgeries on knots in S³ with |p|?1500. Other applications include bounds on the four-ball genera of knots admitting lens space surgeries (which are sharp for Berge's knots), and a constraint on three-manifolds obtained as integer surgeries on alternating knots, which is closely to related to a theorem of Delman and Roberts.     

Leibniz and Hochschild homology

We construct and study the map from Leibniz homology HL_?(𝔥) of an abelian extension 𝔥 of a simple real Lie algebra 𝔤 to the Hochschild homology HH_??1(U(𝔥)) of the universal envelopping algebra U(𝔥). To calculate some homology groups, we use the Hochschild-Serre spectral sequences and Pirashvili spectral sequences. The result shows what part of the non-commutative Leibniz theory is detected by classical Hochschild homology, which is of interest today in string theory.     

The Socle and finite dimensionality of some Banach algebras

The purpose of this note is to describe some algebraic conditions on a Banach algebra which force it to be finite dimensional. One of the main results in Theorem 2 which states that for a locally compact groupG, G is compact if there exists a measure μ in Soc(L ¹(G)) such that μ(G) ≠ 0. We also prove thatG is finite if Soc(M(G)) is closed and every nonzero left ideal inM(G) contains a minimal left ideal.     

Amenability and weak amenability of second conjugate Banach algebras

For a Banach algebra , amenability of necessitates amenability of , and similarly for weak amenability provided is a left ideal in . For a locally compact group, indeed more generally, is amenable if and only if is finite. If is weakly amenable, then is weakly amenable.

     

局部强紧空间的Hoare空间与Smyth空间

本文主要讨论局部强紧空间的性质,特别是其Hoare空间和Smyth空间的性质,证明了T_0空间为局部强紧空间的当且仅当其Hoare空间为局部强紧空间,局部强紧空间的Smyth空间为C-空间.对于强局部紧空间,我们有类似的结论.     

Left-Derived Functors of the Generalized I-Adic Completion and Generalized Local Homology

We study left-derived functors of the generalized I-adic completion and compute these functors by generalized local homology functors.     

Dihedral and quaternionic homology and mapping spaces

We associate to the singular chains of the Moore loop space Y two dihedral chain complexes. The dihedral homology of these complexes is shown to be isomorphic to the O(2)-equivariant homology of the mapping spaces Y ^o(2) and . We also construct simple homotopy theoretic models of EO(2) x _O2 (Y)^G/BO(2) for G = O(2) or S¹, where denotes suspension. Quaternionic analogues of these results are also established.     

Notions of Local Compactness and Smallest Compactifications of Biframes

The category of coherent biframes is shown to be equivalent to that of the coupled lattices, and dually equivalent to the spectral bispaces. Stably continuous biframes arise as the retracts of the coherent biframes. The coherent and the stably continuous biframes are coreflective in all biframes. Weak local compactness is introduced, and in conjunction with regularity, is shown to be sufficient for the construction of smallest compactifications.     

Infinite dimensional affine processes

The goal of this article is to investigate infinite dimensional affine diffusion processes on the canonical state space. This includes a derivation of the corresponding system of Riccati differential equations and an existence proof for such processes, which has been missing in the literature so far. For the existence proof, we will regard affine processes as solutions to infinite dimensional stochastic differential equations with values in Hilbert spaces. This requires a suitable version of the Yamada–Watanabe theorem, which we will provide in this paper. Several examples of infinite dimensional affine processes accompany our results.     

Weight generalization of the space of continuous functions vanishing at infinity

In this paper, we characterize the weighted generalization of the space of continuous functions vanishing at infinity and correct some wrong results in the paper. Let X be a locally compact space and ν is an arbitrary weight (non-negative function) on X. We give a correct and comprehensive definition of the weighted generalization $C_0^{\nu }(X)$ of $C_0(X)$, and show that it is a seminormed space with respect to the canonical seminorm ${\parallel f\parallel }_{\nu }={sup}_{x\in X}|f(x)|$, where $f\in C_0^{\nu }(X)$. We find conditions on ν under which $C_0^{\nu }(X)$, with respect to ${\parallel .\parallel }_{\nu }$, becomes a normed space or a Banach space or an algebra, or a topological algebra, respectively.