Totally nonnegative matrices arise in a remarkable variety of
mathematical applications. This book is a comprehensive and
self-contained study of the essential theory of totally nonnegative
matrices, defined by the nonnegativity of all subdeterminants. It
explores methodological background, historical highlights of key ideas,
and specialized topics.
The book uses classical and ad hoc tools, but a unifying theme is the
elementary bidiagonal factorization, which has emerged as the single
most important tool for this particular class of matrices. Recent work
has shown that bidiagonal factorizations may be viewed in a succinct
combinatorial way, leading to many deep insights. Despite slow
development, bidiagonal factorizations, along with determinants, now
provide the dominant methodology for understanding total nonnegativity.
The remainder of the book treats important topics, such as recognition
of totally nonnegative or totally positive matrices, variation
diminution, spectral properties, determinantal inequalities, Hadamard
products, and completion problems associated with totally nonnegative or
totally positive matrices. The book also contains sample applications,
an up-to-date bibliography, a glossary of all symbols used, an index,
and related references.