Which Numbers Are Real? by Michael Henle
229 Pages, ISBN: 0883857774
Mathematical Association of America
The set of real numbers is one of the fundamental concepts of
mathematics. This book surveys alternative number systems: systems
that generalise the real numbers yet stay close to the properties that
make the reals central to mathematics.
There are many alternative number systems, such as multidimensional
numbers (complex numbers, quarternions), infinitely small and
infinitely large numbers (hyperreal numbers) and numbers that
represent positions in games (surreal numbers).
Each system has a well-developed theory with applications in other
areas of mathematics and science. They all feature in active areas of
research and each has unique features that are explored in this book.
Alternative number systems reveal the central role of the real numbers
and motivate some exciting and eccentric areas of mathematics.
What Numbers Are Real? will be an illuminating read for anyone with an
interest in numbers, but specifically for advanced undergraduates,
graduate students and teachers of university-level mathematics.
http://books.google.com/books?isbn=0883857774
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