The goal of this book is to characterize algebraically the closed
4–manifolds that fibre nontrivially or admit geometries in the
sense of Thurston, or which are obtained by surgery on 2–knots,
and to provide a reference for the topology of such manifolds and
knots. The first chapter is purely algebraic. The rest of the book
may be divided into three parts: general results on homotopy and
surgery (Chapters 2–6), geometries and geometric decompositions
(Chapters 7–13), and 2–knots (Chapters 14–18). In
many cases the Euler characteristic, fundamental group and
Stiefel–Whitney classes together form a complete system of
invariants for the homotopy type of such manifolds, and the possible
values of the invariants can be described explicitly. The strongest
results are characterizations of manifolds which fibre homotopically
over S¹ or an aspherical surface (up to homotopy equivalence)
and infrasolvmanifolds (up to homeomorphism). As a consequence
2–knots whose groups are poly–Z are determined
up to Gluck reconstruction and change of orientations by their
groups alone.
This book arose out of two earlier books: 2–Knots and
their Groups and The Algebraic Characterization of Geometric
4–Manifolds, published by Cambridge University Press for the
Australian Mathematical Society and for the London Mathematical
Society, respectively. About a quarter of the present text has
been taken from these books, and I thank Cambridge University
Press for their permission to use this
material. The arguments
have been improved and the results strengthened, notably in using
Bowditch's homological criterion for virtual surface groups to
streamline the results on surface bundles, using L² methods instead
of localization, completing the characterization of mapping tori,
relaxing the hypotheses on torsion or on abelian normal subgroups in
the fundamental group and in deriving the results on 2–knot
groups from the work on 4–manifolds. The main tools used are
cohomology of groups, equivariant Poincare duality and (to a lesser
extent) L²–cohomology, 3–manifold theory and surgery.
The book has been revised in March 2007 and July 2014. For details see the end
of the preface.