## HOUSTON JOURNAL OF MATHEMATICS

### Archived Edition
Vol. 15, No. 3, 1989

*Editors*: H. Brezis (Paris), J. Hausen (Houston), G.G. Johnson (Houston), J.A. Johnson (Houston), B. Jóhnson (Nashville), A. Lelek (Houston), J. Nagata (Osaka), B.H. Neumann (Australian National University), G.-C. Rota (MIT)

*Managing Editor*: J.W. Neuberger (Emory)

Houston Journal of Mathematics

*Contents*

**Zvi Arad, Hinnit Lipman-Gutweter
**

On Products of Characters in Finite Groups, pp. 305-326.

**D. Arnold, C. Vinsonhaler
**

Quasi-Isomorphism Invariants for a Class of Torsion-Free Abelian Groups, pp. 327-340.

**Robert Stephen Cantrell, Chris Cosner
**

On the Uniqueness and Stability of Positive Solutions in the Lotka-Volterra Competition Model With Diffusion, pp.
341-361.

**Hisao Kato
**

On Local Contractibility at X in Hyperspaces C(X) and 2^{X}, pp. 363-370.

**Judy Kennedy
**

Maps Between Products of One-Dimensional Arcwise Connected Continua, pp.
371-385.

**Alan Lambert
**

An Operator Theoretic Characterization of Isomorphism for Measure Preserving Transformations, pp. 387-394.

**Elizabeth McMahon, Jay Shapiro
**

On Strong and H-Separability in Ordinary and Skew Groups Rings, pp. 395-408.

**Van C. Nall
**

Partially Confluent Maps and n-ods, pp.
409-415.

**Wayne B. Powell, Constantine Tsinakis
**

Disjoint Sets in Free Lattice Ordered Modules, pp. 417-424.

**David Terman
**

Radial Solutions of an Elliptic System: Solutions With a Prescribed Winding Number, pp. 425-458.