A textbook for an honors
linear algebra course (updated Sept. 1, 2014):
Linear Algebra Done Wrong.
by Sergei Treil
From the Introduction:
title of the book sounds a bit mysterious. Why should anyone read this
book if it presents the subject in a wrong way? What is particularly
done "wrong" in the book?
answering these questions, let me first describe the target audience of
this text. This book appeared as lecture notes for the course "Honors
Linear Algebra". It supposed to be a first linear
algebra course for mathematically
advanced students. It is intended for a student who, while not yet very
familiar with abstract reasoning, is willing to study more rigorous
mathematics that is presented in a "cookbook style" calculus type
course. Besides being a first course in linear algebra it is also
supposed to be a first course introducing a student to rigorous
proof, formal definitions---in short, to the style of modern
theoretical (abstract) mathematics.
The target audience explains the very specific blend of elementary
ideas and concrete examples, which are usually presented in
introductory linear algebra texts with more abstract definitions and
constructions typical for advanced books.
Another specific of the book is that it is not written by or for an
algebraist. So, I tried to emphasize the topics that are important for
analysis, geometry, probability, etc., and did not include some
traditional topics. For example, I am only considering vector spaces
over the fields of real or complex numbers. Linear spaces over other
fields are not considered at all, since I feel time required to
introduce and explain abstract fields would be better spent on some
more classical topics, which will be required in other disciplines. And
later, when the students study general fields in an abstract algebra
course they will understand that many of the constructions studied in
this book will also work for general fields.
Also, I treat only finite-dimensional spaces in this book and a basis
always means a finite basis. The reason is that it is impossible to say
something non-trivial about infinite-dimensional spaces without
introducing convergence, norms, completeness etc., i.e. the basics of
functional analysis. And this is definitely a subject for a separate
course (text). So, I do not consider infinite Hamel bases here: they
are not needed in most applications to analysis and geometry, and I
feel they belong in an abstract algebra course.
This book is licensed under a Creative
Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Additional details: You
can use this book free of charge for
non-commercial purposes, in particular for studying and/or teaching.
You can print paper copies of the book or its
parts using either personal printer or professional
Instructors teaching a class (or their institutions) can provide
students with printed copies of the book and charge the fee
to cover the cost of printing; however the students should have an
option to use the free electronic version.
In the new (September 2014) version I corrected
noticed by the readers. I also added some more detailed explanations,
in particular, clearly specifying in all situations whether real
or complex case (or both) is considered.
What is new:
I also expanded a bit sections on non-orthogonal
diagonalization of the quadratic forms, and on singular value
decomposition and its applications. In particular, I added
a section about Moore--Penrose inverse (Section
4.5 in Ch. 6).
Download the book:
you want to see the most up to date version of the book, with all the
noticed typos corrected, you can find it below. The difference
with the version above is only in correrected typos, otherwise the
material is identical. If you printed your version, you do not need to
print a new one; but if you are using an electronic version, it is
better to download the latest vestion.
If you want to see the older versions of the text, you can find it