 
Summary: Algebraic characterizations of graph
imbeddability in surfaces and pseudosurfaces
Lowell Abrams
Department of Mathematics
The George Washington University
Washington DC, 20052
labrams@gwu.edu.
Daniel C. Slilaty
Department of Mathematics and Statistics
Wright State University
Dayton, OH 45435
dslilaty@math.wright.edu.
Abstract
Given a finite connected graph G and specifications for a closed, con
nected pseudosurface, we characterize when G can be imbedded in a
closed, connected pseudosurface with the given specifications. The speci
fications for the pseudosurface are: the number of faceconnected compo
nents, the number of pinches, the number of crosscaps and handles, and
the dimension of the first Z2homology group. The characterizations are
formulated in terms of the existence of a dual graph G
