COMMUNICATIONS IN ALGEBRA
Volume 27, Number 1, 1999
CONTENTS
The Loewy Structure of the Projective Modules of the Mathieu
Group Mi2 and Its Automorphism Group in Characteristic 3 . . . 1
S. Koshitani and K. Waki
The Green Correspondents of the Mathieu Group M^ in
Characteristic 3 . . . 37
S. Koshitani and K. Waki
Double Extension of Quadratic Lie S u p e r a l g e b r a s . . . 67
H. Benamor and S. Benayadi
Co-Cohen-Macaulayness of Certain Graded Artinian M o d u l e s . . . 89
Z. Tang and G. Zhu
On Two Open Problems About Embedding of Modules in Free
Modules . . . 105
J . Rada and M. Saorin
Extended Root Graphs for Complex Reflection Groups . . . 119 M. Hughes
A Minimality Property of Rees V a l u a t i o n s . . . 149
A. Nobile
Vertex-Primitive Vi -Arc-Transitive Graphs of Smallest Order . . . 163 S.-F. DuandM.-Y. Xu
Maximal Orders in Semigroups . . . 173
J . Fountain, V. Gould, and P. Smith
Direct Topologies from Discrete Rings. II. . . . 189 N. Shell
Quasi-P Radicals of r - R i n g s . . . 219 W. Chen
(continued on inside back cover)
M A R C E L
MARCEL DEKKER, INC. NEW YORK • BASEL
Contributions to this journal are published free of charge
D E K K E R
COMMUNICATIONS IN ALGEBRA
Volume 27, Number 2, 1999
CONTENTS
Cyclic Representations of the Quantum Matrix Algebras . . . 493 H. P. Jakobsen and H. Zhang
On the Structure of Cohen-Macaulay Simplicial AfTine
S e m i g r o u p s . . . 511 J. C. Resales and P. A. Garcia-Sdnchez
Elementary Groups and Invertibility for Kantor Pairs . . . 519 B. N. Allison and J. R. Faulkner
Products of Involutions in the Groups of Lie Type F ^ K ) . . . 557
P. C. Austin
Gerbes and Covers . . . 577 P. Debes andJ.-C. Douai
Enlargements, Semiabundancy, and Unipotent M o n o i d s . . . 595
J . Fountain, G. M. S. Gomes, and V. Gould
On the Cohomological 2-Dimension of F i e l d s . . . 615
R. Elman and C. Lum
A Note on the Wielandt Subgroup of a Metabelianp-Group... 621
E. A. Ormerod
Kaplansky Fields and ^-Algebraically Closed Fields . . . 629 P. Vamos
Hochschild Cohomology of Truncated Quiver Algebras . . . 645 A. C. Locateli
Rings Having a Morita-Like E q u i v a l e n c e . . . 665
J . L. Garcia and L. Marin
Large Subdirect Products of Graded M o d u l e s . . . 681
L. Oyonarte and B. Torrecillas
An Explicit Sign Formula for the Determinant of Cohomology... 703 W. Aitken
vii
viii CONTENTS The Homotopy Type of Spaces X with Fundamental Groupoid Q
and an Unique Non-trivial Homotopy ^-Module Fin (X) . . . 725
M. Bullejos and J . G. Cabello
Intertwining Operators Between Some Spaces of Differential
Operators on a Manifold . . . 755
P. Mathonet
Generalized Verma Modules over the Lie Algebra of Type G^ . . . Ill
A. Khomenko and V. Mazorchuk
On a Characterization of Perfect Rings . . . 785
N. Ding and J . Chen
Differential Identities of Lie Ideals or Large Right Ideals in
Prime Rings . . . 793
T.-K. Lee
Residual Division, Primary Decomposition, and Filtrations.
Application to Dedekind Domains . . . 811
K. E. Abalo and D. N. Niango
Algebraic Extensions of Graded and Valued F i e l d s . . . 821
V.-5. Hwang and A. R. Wads-worth
Twisted Flag Varieties of Trialitarian G r o u p s . . . 841 R. S. Garibaldi
The Automorphism Group and the Picard Group of a Monomial
A l g e b r a . . . 857
F. Guil-Asensio and M. Saorin
On Some Classes of /P-Modules and Congruences in /?-Tors . . . 889
F. Raggi, H. Rincon, and C. Signoret
A PBW Basis for Lusztig's Form of Untwisted Affine Quantum
Groups . . . 903 F. Gavarini
Almost Finite Modules . . . 919 D. Apassov
Jordan Centroids . . . 933
K. McCrimmon
CONTENTS ix On the Isomorphism Problem for Finite Dimensional Diagram
Algebras . . . 955
W. D. Burgess andJ.-B. Du
S-Pure-Injective Modules over a Commutative Priifer Ring . . . 961
M. Prest and G. Puninski
New Simple Infinite Dimensional Lie Algebras Related to Those of
Generalized Cartan Type H . . . 973 V. Jia
