Ebook: Sheaf Theory

This book is primarily concerned with the study of cohomology theories of general topological spaces with "general coefficient systems. " Sheaves play several roles in this study. For example, they provide a suitable notion of "general coefficient systems. " Moreover, they furnish us with a common method of defining various cohomology theories and of comparison between different cohomology theories. The parts of the theory of sheaves covered here are those areas impor­ tant to algebraic topology. Sheaf theory is also important in other fields of mathematics, notably algebraic geometry, but that is outside the scope of the present book. Thus a more descriptive title for this book might have been Algebraic Topology from the Point of View of Sheaf Theory. Several innovations will be found in this book. Notably, the con­ cept of the "tautness" of a subspace (an adaptation of an analogous no­ tion of Spanier to sheaf-theoretic cohomology) is introduced and exploited throughout the book. The fact that sheaf-theoretic cohomology satisfies 1 the homotopy property is proved for general topological spaces. Also, relative cohomology is introduced into sheaf theory. Concerning relative cohomology, it should be noted that sheaf-theoretic cohomology is usually considered as a "single space" theory.

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This book is primarily concerned with the study of cohomology theories of general topological spaces with "general coefficient systems." The parts of sheaf theory covered here are those areas important to algebraic topology. There are several innovations in this book. The concept of the "tautness" of a subspace is introduced and exploited throughout the book. The fact that sheaf theoretic cohomology satisfies the homotopy property is proved for general topological spaces. Relative cohomology is introduced into sheaf theory. The reader should have a thorough background in elementary homological algebra and in algebraic topology. A list of exercises at the end of each chapter will help the student to learn the material, and solutions of many of the exercises are given in an appendix. The new edition of this classic in the field has been substantially rewritten with the addition of over 80 examples and of further explanatory material. Among the items added are new sections on Cech cohomology, the Oliver transfer, intersection theory, generalized manifolds, locally homogeneous spaces, homological fibrations and