This is the third edition of a classic text,
previously published in 1968, 1988, and now extended,
revised, retitled, updated, and reasonably priced.
Throughout it gives motivation and context for theorems
and definitions. Thus the definition of a topology is
first related to the example of the real line; it is
then given in terms of the intuitive notion of
neighbourhoods, and then shown to be equivalent to the
elegant but spare definition in terms of open sets. Many
constructions of topologies are shown to be necessitated
by the desire to construct continuous functions, either
from or into a space. This is in the modern categorical
spirit, and often leads to clearer and simpler proofs.
There is a full treatment of finite cell complexes, with
the cell decompositions given of projective spaces, in
the real, complex and quaternionic cases. This is based
on an exposition of identification spaces and adjunction
spaces. The exposition of general topology ends with a
description of the topology for function spaces, using
the modern treatment of the test-open topology, from
compact Hausdorff spaces, and so a description of a
convenient category of spaces (a term due to the author)
in the non Hausdorff case. The second half of the book
demonstrates how the use of groupoids rather than just
groups gives in 1-dimensional homotopy theory more
powerful theorems with simpler proofs. Some of the
proofs of results on the fundamental groupoid would be
difficult to envisage except in the form given: `We
verify the required universal property'. This is in the
modern categorical spirit. Chapter 6 contains the
development of the fundamental groupoid on a set of base
points, including the background in category theory. The
proof of the van Kampen Theorem in this general form
resolves a failure of traditional treatments, in giving
a direct computation of the fundamental group of the
circle, as well as more complicated examples. Chapter 7
uses the notion of cofibration to develop the notion of
operations of the fundamental groupoid on certain sets
of homotopy classes. This allows for an important
theorem on gluing homotopy equivalences by a method
which gives control of the homotopies involved. This
theorem first appeared in the 1968 edition. Also given
is the family of exact sequences arising from a
fibration of groupoids. The development of Combinatorial
Groupoid Theory in Chapter 8 allows for unified
treatments of free groups, free products of groups, and
HNN-extensions, in terms of pushouts of groupoids, and
well models the topology of gluing spaces together.
These methods lead in Chapter 9 to results on the
Phragmen-Brouwer Property, with a Corollary that the
complement of any arc in an n-sphere is connected, and
then to a proof of the Jordan Curve Theorem. Chapter 10
on covering spaces is again fully in the base point free
spirit; it proves the natural theorem that for suitable
spaces X, the category of covering spaces of X is
equivalent to the category of covering morphisms of the
fundamental groupoid of X. This approach gives a
convenient way of obtaining covering maps from covering
morphisms, and leads easily to traditional results using
operations of the fundamental group. Results on
pullbacks of coverings are proved using a Mayer-Vietoris
type sequence. No other text treats the whole theory
directly in this way. Chapter 11 is on Orbit Spaces
and Orbit Groupoids, and gives conditions for the
fundamental groupoid of the orbit space to be the orbit
groupoid of the fundamental groupoid. No other topology
text treats this important area. Comments on the
relations to the literature are given in Notes at the
end of each Chapter. There are over 500 exercises, 114
figures, numerous diagrams. See
http://www.bangor.ac.uk/r.brown/topgpds.html for more
information. See
http://mathdl.maa.org/mathDL/19/?rpa=reviews&sa=viewBook&
bookId=69421 for a Mathematical Association of America
review.
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