Transactions of the AMS. Year 1966. Volume 123. Number 02.


Hausdorff measures on abstract spaces
M. Sion; R. C. Willmott
275-309


Compactification and duality of topological groups
Hsin Chu
310-324


Finite topological spaces
R. E. Stong
325-340


Bol loops
D. A. Robinson
341-354


Tame surfaces and tame subsets of spheres in $E\sp{3}$
L. D. Loveland
355-368


Elastic-plasitc torsion of a square bar
Tsuan Wu Ting
369-401


Limit theorems for semi-Markov processes
James Yackel
402-424


The level curves of harmonic functions
Leopold Flatto; Donald J. Newman; Harold S. Shapiro
425-436


Dilations on invertible spaces
Ellard Nunnally
437-448

Abstract: This paper primarily concerns certain groups of homeomorphisms which are associated in a natural way with a variety of spaces, which satisfy a set of axiomatic conditions put forth in §1. Let us suppose that $X$ is a space of the type in question and that $G$ is an appropriate group of homeomorphisms of $ X$ onto itself. In §2 we demonstrate the existence of a nonvoid subcollection $ \mathcal{D}$, the ``topological dilations,'' of $G$ which is characterized in Theorem 1 in the following fashion: suppose $f \in \mathcal{D}$ and $g \in G$, then $ g \in \mathcal{D}$ if and only if $f$ is a $G$-conjugate of $g$, that is if and only if there exists an element $ h$ of $G$ such that $f = hg{h^{ - 1}}$. We proceed then to show in §3 that if $f$ and $g$ are nonidentity elements of $G$, then we may find $\delta ,r \in G$ such that the product $(rg{r^{ - 1}})(\delta f{\delta ^{ - 1}}) \in \mathcal{D}$. We then combine this fact with the characterization of $ \mathcal{D}$ mentioned above to conclude that each element of $\mathcal{D}$ is a ``universal'' element of $ G$ in the sense that if $d \in \mathcal{D}$, then any element $g$ of $G$ may be represented as the product of two $ G$-conjugates of $ d$. Furthermore we conclude that if $g$ is not the identity element of $G$, then $g$ can be represented as the product of three $ G$-conjugates of any nonidentity element of $G$. Finally, we apply the conclusions to groups of homeomorphisms of certain spaces: for example spheres, cells, the Cantor set, etc.


Decay at infinity of solutions to partial differential equations with constant coefficients
Walter Littman
449-459


Decomposable chainable continua
J. B. Fugate
460-468


Regular minimal sets. I
Joseph Auslander
469-479


Unknotting in $M\sp{2}\times I$
E. M. Brown
480-505


Polynomial automorphic forms and nondiscontinuous groups
Marvin Isadore Knopp
506-520


Singular perturbations on the infinite interval
Frank Charles Hoppensteadt
521-535


On Witt's theorem in the denumerably infinite case
Herbert Gross
536-547


Errata to ``Szeg\"o functions on a locally compact Abelian group with ordered dual''
I. I. Hirschman
548