-- TITLE --
	
	"Central p-group extensions: 
	 Laudal obstruction spaces revisited"

-- ABSTRACT --

	 "In a recent attack on the modular isomorphism problem, 
	  Borge and Laudal have introduced the concept of obstruction spaces.
	  This paper contains an introduction and characterization of 
	  obstruction spaces for diagrams of central p-group extensions. 
	  We also relate obstruction spaces with certain universal short exact
	  sequences derived from the lower p-central and 
	  Brauer--Jennings--Zassenhaus series of arbitrary finite p-groups.
	  Finally, we discuss the connection of these results with the modular
	  isomorphism problem."

-- STATUS --

	  Submitted for publication

-- AUTHORS --

	 Martin Hertweck	and
	 Marcos Soriano

___________________________________________________________________________

Dr. Martin Hertweck                                         Office:  7.561
Universitaet Stuttgart                           Phone:   +49 711 685 5320
Fachbereich Mathematik
Institut fuer Geometrie und Topologie            Fax:     +49 711 685 5304
Lehrstuhl fuer Differentialgeometrie
Pfaffenwaldring 57
70550 Stuttgart
Germany

homepage: http://www.igt.uni-stuttgart.de/LstDiffgeo/Hertweck/
___________________________________________________________________________

Dr. Marcos Soriano                                          Office:  A 452
Universitaet Hannover                            Phone:   +49 511 762 4243
Institut fuer Mathematik
Lehrgebiet Algebra und Zahlentheorie             Fax:     +49 511 762 5490
Welfengarten 1
30167 Hannover
Germany

homepage: http://www-ifm.math.uni-hannover.de/~soriano/
___________________________________________________________________________