A compact group action which raises dimension to infinity

Compact group actions that raise dimension to infinity

THEOREM. For every prime $p$ and each $n=2, 3, ... \infty$, there is an action of $G=\prod_{i=1}^{\infty}(Z/ pZ)$ on a two-dimensional compact metric space $X$ with $n$-dimensional orbit space. This theorem was proved in [DW: A.N. Dranishnikov and J.E. West, Compact group actions that raise dimension to infinity, Topology and its Applications 80 (1997), 101-114] with an error in one of the lemmas (Lemma 15). This paper presents a corrected version of Lemma 15 and it is identical with [DW] in the rest.

无穷远处的链接与非紧致流形上的标量曲率衰减

Linking at Infinity and Scalar Curvature Decay on Non-Compact Manifolds

研究非紧致正标量曲率流形上曲率衰减与无穷远处拓扑结构的关系，证明拓扑链接迫使弱有界几何流形上标量曲率多项式衰减，并发展局部于非紧致流形端点的障碍理论。

Manifolds with non-stable fundamental groups at infinity, II

In this paper we continue an earlier study of ends non-compact manifolds. The over-arching goal is to investigate and obtain generalizations of Siebenmann's famous collaring theorem that may be applied to manifolds having non-stable fundamental group systems at infinity. In this paper we show that, for manifolds with compact boundary, the condition of inward tameness has substatial implications for the algebraic topology at infinity. In particular, every inward tame manifold with compact boundary has stable homology (in all dimensions) and semistable fundamental group at each of its ends. In c…

Manifolds with non-stable fundamental groups at infinity, III

We continue our study of ends non-compact manifolds. The over-arching aim is to provide an appropriate generalization of Siebenmann's famous collaring theorem that applies to manifolds having non-stable fundamental group systems at infinity. In this paper a primary goal is finally achieved; namely, a complete characterization of pseudo-collarability for manifolds of dimension at least 6.

Affine cubic surfaces and relative SL(2)-character varieties of compact surfaces

A natural family of affine cubic surfaces arises from SL(2)-characters of the 4-holed sphere and the 1-holed torus. The ideal locus is a tritangent plane which is generic in the sense that the cubic curve at infinity consists of three lines pairwise intersecting in three double points. We show that every affine cubic surface which is smooth at infinity and whose ideal locus is a generic tritangent plane arises as a relative SL(2)-character variety of the 4-holed sphere. Every such affine cubic for which all the periodic automorphisms of the tritangent plane extend to automorphisms of the cubic…

Simplicial volume of closed locally symmetric spaces of non-compact type

We show that compact, locally symmetric spaces of non-compact type have positive simplicial volume. This gives a positive answer to a question that was first raised by Gromov in 1982. We provide a summary of results that are known to follow from positivity of the simplicial volume.