[HN Gopher] Free Math Books
       ___________________________________________________________________
        
       Free Math Books
        
       Author : blewboarwastake
       Score  : 291 points
       Date   : 2021-01-19 09:12 UTC (13 hours ago)
        
 (HTM) web link (klkuttler.com)
 (TXT) w3m dump (klkuttler.com)
        
       | tomcam wrote:
       | What an amazing amount of work to give the world for free. Thank
       | you.
        
       | phonebucket wrote:
       | Another solid source of free math resources:
       | https://realnotcomplex.com/
        
       | cpp_frog wrote:
       | In college I was taught Linear Algebra from the operator point of
       | view, rather than with matrices. That way theorems are clearer
       | and the student's understanding is deeper, but for applications
       | it's better to study from the matrix point of view and with lots
       | of examples. Kuttler's book was refreshing in that sense. His
       | other books are excellent, too. If you have been studying pure
       | math (or french-style applied math which is just pure math with a
       | concentration in Analysis) they are a light and fun complementary
       | read.
        
         | lr1970 wrote:
         | The best, by far, book on Linear Algebra that elegantly teaches
         | it from Vector Spaces and Linear Operators point of view is
         | 
         | Paul Halmos "Finite-Dimensional Vector Spaces"
         | 
         | For instance, the way Halmos introduces the determinant of a
         | matrix (or an operator) is the most consistent, elegant and
         | simple way I ever encountered. OTOH, in Kenneth Kuttler's
         | LinAlg books the determinant is pulled out of the thin air like
         | in 1000+ other similar books.
        
           | cpp_frog wrote:
           | Thanks, I'll look it up. The best textbook from which I
           | studied (operators) was Elon Lima's Algebra Linear. Sadly the
           | only physical copies are sold in Brazil.
        
             | spekcular wrote:
             | If you want to see the matrix point of view done well,
             | there's _Linear Algebra Done Wrong_ :
             | https://www.math.brown.edu/streil/papers/LADW/LADW.html.
             | You can read a bit about the motivation for doing it that
             | way on that website.
             | 
             | The title is a reference to a somewhat well-known book,
             | _Linear Algebra Done Right_ , which avoids using
             | determinants to develop the theory (resulting in a somewhat
             | novel/cleaner presentation). It's unfortunately not freely
             | available online (published by Springer - I would suspect
             | most university students can get it freely through their
             | library's website, however).
        
               | Tomte wrote:
               | LADR was freely available at Springer at least at some
               | point in time. Under their open access program. I
               | couldn't find it again in a few minutes' search, so it
               | may be gone.
        
             | in9 wrote:
             | Ah yes, a fellow Brazillian. I've alwys found Elon's book
             | on Linear Algebra a masterpiece. Coupled with the exercises
             | book, going through it is an eye opening experience.
        
           | enriquto wrote:
           | While Halmos' book is lovely, I still prefer the geometric
           | definition of determinant to the algebraic one: The
           | determinant of a matrix is the signed volume (or area) of the
           | parallellepiped spanned by its columns. Equivalently, the
           | determinant of a linear map is the volume of the image of a
           | unit cube by that map (or any arbitrary shape of volume one,
           | not necessarily a cube). All the algebraic properties of the
           | determinant follow easily from the geometric definition
           | (multi-linearity, anti-symmetry, etc).
           | 
           | Really, I don't see what you like about Halmos definition of
           | the determinant... I have just read it (page 99 of my copy)
           | and he admits that it is a "somewhat roundabout procedure",
           | just after giving the definition! There's other references
           | that seem much cleaner (e.g. Spivak's calculus on manifolds,
           | using exterior algebra).
        
             | lr1970 wrote:
             | > Really, I don't see what you like about Halmos definition
             | of the determinant...
             | 
             | Halmos shows (it is almost trivial) that the space of anti-
             | symmetric n-forms Wn over L_n is 1-dimensional.
             | Wn(Ae1,...,Aen) = const*Wn(e1,...,en). This scalar const is
             | called determinant. It has all the properties you would
             | ascribe to Volume like volume spanned by collinear column-
             | vectors is zero. This is a nice bridge to geometry in Ln.
             | Also, in a space of just one page (p.99) he introduces
             | determinant and proves its main properties like det(A*B) =
             | det(A)*det(B) and therefore det(A^-1) = 1/det(A).
        
               | jacobolus wrote:
               | The determinant of n vectors {vi} relative to a
               | particular basis {ei} in an n-dimensional vector space is
               | the scalar-valued ratio:
               | 
               | ( v1 [?] v2 [?] *** [?] vn ) / ( e1 [?] e2 [?] *** [?] en
               | )
               | 
               | The signed volume per se is just the n-vector: v1 [?] v2
               | [?] *** [?] vn
               | 
               | Generally working with the wedge product is more pleasant
               | and conceptually clearer than working with determinants.
               | Among other things we don't need to make an arbitrary
               | choice of basis or unit n-vector. There's also no reason
               | to limit ourselves to n terms. v1 [?] v2 is also a
               | reasonable quantity to use, etc.
        
               | lr1970 wrote:
               | The beauty of Halmos' derivation, which is similar but
               | not identical to exterior algebra (wedge product), is
               | that his approach is basis independent. A determinant by
               | his definition is scalar invariant over all bases. It is
               | very geometrical in nature.
        
               | jacobolus wrote:
               | The determinant inherently involves a basis (or at the
               | very least a choice of unit n-vector). Or if you like you
               | can think of the determinant as a function of a square
               | matrix (grid of numbers), rather than a function of a
               | collection of vectors.
               | 
               | When you take the basis out, that's the wedge product,
               | which inherently includes the orientation. Conveniently,
               | there is only one degree of freedom for n-vectors in
               | n-dimensional space. When we take the quotient of two
               | n-vectors in n-dimensional space we therefore get a
               | scalar.
        
             | The_suffocated wrote:
             | If you define determinant as volume, how do you define
             | volume? I agree that it's pedagogically sound to _motivate_
             | the notion of determinant by the volume of a
             | parallelepiped, but using volume as the _definition_ of
             | determinant just doesn 't sound right.
             | 
             | And strictly speaking, determinant is not volume because
             | the former is dimensionless. It is the scaling factor of
             | the volume when a geometric entity is transformed by a
             | linear map.
        
               | enriquto wrote:
               | > If you define determinant as volume, how do you define
               | volume?
               | 
               | How do you define "length" and "area"? I guess that if
               | you don't have already a very firm grasp of these basic
               | concepts, then there's no business for you (yet) in
               | studying determinants. Much later, once you master
               | thoroughly lengths, areas, volumes and hypervolumes; and
               | also linear algebra and determinants (however they are
               | defined), then you can embark in the elegant definitions
               | using exterior algebra and the like. Notice that Halmos
               | itself says that his treatment is appropriate for a
               | *second* course in linear algebra, preparing the field
               | for the later study of infinite-dimensional spaces.
               | 
               | > And strictly speaking, determinant is not volume
               | because the former is dimensionless.
               | 
               | This really depends on the context. If you are working on
               | euclidean space, you already have "units" and the
               | determinant makes sense in itself, as the volume spanned
               | by sets of vectors.
        
           | [deleted]
        
           | ABeeSea wrote:
           | I find both the geometric and algebraic definitions quoted
           | here unsatisfying. What is a "volume" spanned by a vector
           | space of polynomials or co-tangent functionals?
           | 
           | *A* determinate function (not the) is simply a skew symmetric
           | n-linear map into the underlying field.
           | 
           | Done. Now we get the volume interpretation when it's
           | appropriate, the wedge product interpretation, and the
           | generalization to finitely generated projective modules (if a
           | determinate function exists, there are additional conditions
           | needed for the existence.)
        
         | mhh__ wrote:
         | Although I understand that matrix-soup is kind of the entropic
         | endstate of all high school mathematics pedagogy, I think it is
         | a real tragedy: In the UK especially even the best and
         | brightest barely touch any real mathematics until after they
         | leave secondary school so they leave with almost literally no
         | idea of what university mathematics consists of. It's all well
         | and good training people to be engineers, but the universities
         | end up teaching the whole syllabus to them again in about 6
         | weeks. It's just shit.
         | 
         | The only reason why I am now doing theoretical physics (I was
         | in the dumb group initially and worked my way up largely by
         | myself) is because I read a calculus textbook by accident and
         | got hooked when I was 14. Even when I made it to the top of the
         | pile I still wasn't allowed to do anything more than calculus
         | because the module system means we had to choose _as a class_
         | whether to do group theory or not.
        
           | cpp_frog wrote:
           | I understand, I too had a similar experience in high school.
           | My comment was largely referring to my context: This semester
           | I'll finish a mathematical engineering degree (in my country
           | engs. are 12 semesters long) and the abstract way is
           | rewarding but without applications can only be endured so
           | far. It does not help that a large fraction of mathematical
           | engineers after they graduate end up doing some software work
           | consisting in statistics, optimization or some other advanced
           | mathetical concept. With a dropout rate of ~80%, not many
           | people are willing to put themselves through rigorous
           | analysis classes on top of the engineering requirements for
           | so many years to get a job doing something you could have
           | learned in a more practical way. But we are very well paid
           | and the unemployment rate is 0% since there are maybe 10
           | graduates in the whole country each year.
        
           | 2wrist wrote:
           | Good luck to you. I wish you every success. The education in
           | this country has been shit for such a long time. It is and
           | has been pretty devastating for so long.
           | 
           | Apologies for the negative waves.
        
             | mhh__ wrote:
             | No negativity measured, actually
        
               | [deleted]
        
         | fangyrn wrote:
         | Could you please talk about alternative ways of learning about
         | linear algebra?
        
       | amelius wrote:
       | Are the answers to the exercises to be found somewhere?
        
         | AlphENsign_Tech wrote:
         | wolfram alpha?
        
         | AcademicHamster wrote:
         | Probably not. That's why most of these books are useless for
         | people that self-study. There isn't an external feedback
         | mechanism to check your work. I'd recommend hiring a tutor. You
         | can post online too, but the answers to your questions may
         | vary.
        
           | commandlinefan wrote:
           | I never understood why they do that - especially for
           | something like this that's offered for free. What's the point
           | of even including the exercises if there's no way to check
           | the answers?
        
             | AcademicHamster wrote:
             | I wondered the same. I have no idea, other than to
             | speculate. In this case, it might be out of habit (since
             | this is usually how textbooks are written) or laziness. I
             | can't recommend any of these books for self-studies unless
             | the person studying is fine with posting every exercise
             | they do online for correctness checks or can hire a tutor.
        
               | carapace wrote:
               | It's really hard to do (at all, let alone well) but the
               | point is to encode more information in the problems such
               | that, by solving them oneself, the student gains direct
               | understanding of some technique or application or
               | extension that wasn't covered in the main text. In a
               | (well-written) textbook there might be five or tens times
               | as much information latent in the (solving of the)
               | exercises than in the entire preceding chapter. Writing
               | these kinds of sets of exercises is very challenging,
               | much harder than just writing a textbook.
        
       | visarga wrote:
       | Off topic: nice PDF rendering I wish normal PDF would be as
       | fluent.
        
         | lightspot21 wrote:
         | Indeed, LaTeX makes for really awesome results if you can put
         | in the time to learn it (which is not a lot for basic usage).
         | Plus it helps enforce a common style in all docs, and works
         | well with Git.
        
       | xanax wrote:
       | I like this. The more free information the better.
        
       | amilein7minutes wrote:
       | Did the same person write all these books, which altogether
       | amount to upwards of 10k pages? From his website, he is quite an
       | active research mathematician too. While just writing so many
       | textbooks is a huge accomplishment in itself, the author has also
       | made them available for free; I am lost for words at how prolific
       | as well as generous the author is. I really want to know how this
       | was possible, how long it took, and more about their motivation.
        
       | opheliate wrote:
       | Wow, these look great! Does anyone know of any similar resources
       | for mechanics, specifically the Hamiltonian & Lagrangian
       | formulations? I've had a bit of trouble finding good resources
       | online to supplement my mechanics modules at uni.
        
         | posix_me_less wrote:
         | Tong is good, most appropriate if you already know a little
         | about the subject. However, it is a "fast-track" kind of
         | resource, it is good to read some standard textbooks on the
         | subject, i.e. Landau & Lifshitz (the most efficient book on
         | theoretical mechanics ever) and Goldstein (broad and
         | interesting).
        
           | mhh__ wrote:
           | Although I have immense respect for them I really don't like
           | L&L all that much. The first one is pretty beautiful but it
           | could use some material on the "deeper" side of things,
           | particularly the connection with geometry and Noether's
           | theorem. As for the others, they're just too "russian" - I
           | like how oddly practical they are, but they're just not
           | structured properly - StatPhys in particular just doesn't
           | flow very well.
           | 
           | The typesetting is also a crime against humanity - they
           | should be done similarly to the Feynman lectures, so typed up
           | in LaTeX rather than whatever they are now
        
             | enriquto wrote:
             | > could use some material on the "deeper" side of things
             | 
             | The first few chapters are precisely about the extraction
             | of concrete conserved quantities from symmetries. A
             | sufficiently "russian" reader will be able to see
             | immediately the general case from these very complete
             | examples. Noether's theorem is only missing in name, not in
             | content.
             | 
             | > The typesetting is also a crime against humanity - they
             | should be done similarly to the Feynman lectures, so typed
             | up in LaTeX rather than whatever they are now
             | 
             | The typeseting of the french edition of L&L is
             | extraordinarily beautiful. I'm not sure that is is possible
             | to reach this typographical elegance with freely available
             | LaTeX packages. On the other hand, the re-typed Feynman
             | lectures are a disgrace, and an objectively worsening in
             | quality from the first editions.
        
               | mhh__ wrote:
               | I liked that section a lot but I want a jumping off
               | point. I don't think symmetries of the action or groups
               | are discussed, IIRC.
               | 
               | I may have been a little vague when I said typesetting -
               | the actual typesetting is a bit dull but the thing that
               | is a disgrace, I should clarify, is that the fonts are
               | terrible, and the text has that "Cheap Dover book" print
               | quality (not far off a good typewriter).
        
               | spekcular wrote:
               | To amplify this point, all the negative Amazon reviews
               | praise the book but excoriate the print quality.
        
               | enriquto wrote:
               | This must concern some paperback English print? My copy
               | in French from "Editions MIR Moscou, 1969", hardcover,
               | masterfully typeset and in bible paper is one of the
               | finest books that I have.
        
               | spekcular wrote:
               | Yes, I think it's specific to the English version. You
               | can see examples if you use the Amazon.com "look inside"
               | feature. For instance in volume 3, in the first pages
               | already some of the footnotes are hardly readable.
               | 
               | For one of the volumes, a reviewer even posted a picture
               | of his edition with subscripts printed so faint/partially
               | that they were basically missing, and he had to Google
               | the proper formulas!
        
               | mhh__ wrote:
               | Yes, I literally have RF engineering books (interesting
               | reads actually) that are as old as my grandfather that
               | have clean equations and beautiful text, in a lovely
               | binding, but my L&L copies are both like an n-th order
               | photocopy.
        
             | posix_me_less wrote:
             | Regarding geometry and Noether's theorem, I disagree. That
             | stuff is way overblown in general, it gives you very little
             | ( in classical mechanics) for the time and page count the
             | subject requires. I had a lecture on this topic from
             | enthusiast well-respected physicist, and I kept thinking,
             | this stuff is interesting math but completely useless to a
             | physicist.
        
               | mhh__ wrote:
               | Classical mechanics is ultimately just masturbation
               | compared to the "real thing", it's all a warm-up for the
               | mind rather than teaching you how to calculate stresses
               | on a beam - Full on symplectic geometry is niche but the
               | basics of Noether's theorem and symmetries are central to
               | classical and quantum field theories which are ultimately
               | the language in which the cutting edge of fundamental
               | physics speaks.
               | 
               | So I sort of agree, but take the two Oxford books on QFT
               | and Statistical physics - they pack in enormous amounts
               | of detail in a 3 or 4 hundred pages. There's room to
               | spare if the book is the right shape.
        
               | spekcular wrote:
               | What are the titles of the two Oxford books you
               | mentioned? I'd like to look at them.
        
               | mhh__ wrote:
               | Quantum Field Theory for the gifted amateur (well not
               | quite...)
               | 
               | Concepts in thermal physics
               | 
               | Not at the same level as L&L but they are absolute
               | masterpieces in pedagogy and the formula should be
               | extended to a 800page tome to cover more material. It's
               | the way MTW should be written...
        
             | spekcular wrote:
             | Yeah, I liked the mechanics and quantum volumes, but the
             | choice of material in the stat mech books (both volumes)
             | just seemed weird compared to what's usually done in a
             | modern graduate course.
             | 
             | Do you have any recommendations for good stat mech books? I
             | guess the two volume set by Kardar is trendy right now, but
             | I'm always curious about other options.
        
               | mhh__ wrote:
               | I'm remiss to recommend as I'm still learning, but I
               | absolutely love "Concepts in Thermal physics". It's
               | embarrassingly well written and structured.
               | 
               | Beyond that the usual suspects are good enough for me, I
               | just don't _like_ L &L. I'm probably forgetting
               | something.
               | 
               | It's not exactly statmech but I really like McComb's
               | introductory renormalization methods book.
        
               | spekcular wrote:
               | Thank you for the recommendations!
               | 
               | While I have not seen either of those books before, I
               | have another book by the author of the first one, Stephen
               | Blundell. It's _Quantum Field Theory for the Gifted
               | Amateur_ , and I think you might like it. Not as a
               | standalone quantum book, but perhaps as a supplement to a
               | more "serious" treatment.
               | 
               | edit: I just saw you recommended this below!
        
               | mhh__ wrote:
               | QFTFTGA is really great. Surprisingly hard as well.
               | 
               | I got it when I was 17 and it was an absolute godsend as
               | its really cheap.
        
         | mhh__ wrote:
         | Based on "uni" I'm guessing you are at a UK institution (as am
         | I).
         | 
         | The notes are utter dogshit because there's no culture of
         | publishing them online for the public.
         | 
         | Kibble's classical mechanics book is deep, easy to read and
         | cheap, I'd start there. Most physics books past a certain level
         | end up with an increasingly hand-wavy derivation of the Euler-
         | lagrange equations in some context
        
         | abhinav22 wrote:
         | Look for Dover books, particularly from Russian authors. Cheap
         | and good!
        
           | Tomte wrote:
           | For linear algebra: Shilov.
        
         | blewboarwastake wrote:
         | I found these lecture notes by David Tong to be really good at
         | a glance [1]. A free introductory physics book [2]. I don't
         | have much physics stuff and I know almost nothing about it, I
         | mostly focus on Math/CS, this is some stuff that I had
         | bookmarked. Maybe someone else here can share some good
         | Mechanics resources.
         | 
         | [1] http://www.damtp.cam.ac.uk/user/tong/dynamics.html [2]
         | http://www.lightandmatter.com
        
       | posix_me_less wrote:
       | Does anybody know of an awesome list that has more of these kinds
       | of "pdf textbooks" on math/phys/engineering?
        
         | ivan_ah wrote:
         | Not sure if you needed PDF specifically, but this site has a
         | lot of good OER textbooks, digitized nicely as HTML + MathJax:
         | https://math.libretexts.org/Bookshelves
        
         | mvalcic wrote:
         | Check out the Open Textbook Library:
         | 
         | https://open.umn.edu/opentextbooks/
        
           | aungmyohtet wrote:
           | Thank you.
        
         | enriquto wrote:
         | > Does anybody know of an awesome list that has more of these
         | kinds of "pdf textbooks" on math/phys/engineering?
         | 
         | Go to John Baez's awesome list "How to Learn Math and Physics":
         | 
         | https://math.ucr.edu/home/baez/books.html
         | 
         | And then to Library Genesis.
        
           | human4fter4ll wrote:
           | Thank you so much!
        
         | mathnmusic wrote:
         | I have been adding a number of these free books at
         | https://learnawesome.org/
         | 
         | Do you really care about the format being PDF or is it about
         | the books being FREE? I'd like to make common queries like
         | yours easier. LearnAwesome is open-source, so of course you're
         | free to contribute: https://github.com/learn-awesome/learn
        
           | mattowen_uk wrote:
           | Oooh this is like a dmoz.org list from yesteryear when the
           | web was _useful_. Bookmarked, Cheers!
        
           | Spooky23 wrote:
           | Nerds love to bike shed crap like this and bite the hand that
           | feeds.
           | 
           | To paraphrase a typical rant: "Making knowledge free and
           | accessible is useless unless a libre format is used like
           | Markdown." Lol
           | 
           | The PDF beef is funnier in that people usually don't know why
           | they are morally opposed to PDF, it usually boils down to not
           | liking Adobe Acrobat a decade ago, not accepting that page
           | format preservation is a thing, or some beef with zooming or
           | something. End of the day, it seeks to be digital paper.
           | 
           | End of the day, it's an open standard with multiple
           | implementations. Just by virtue of the US Federal Courts
           | using it for millions of documents it will be usable for the
           | foreseeable future, well beyond our lifetimes. (And there are
           | many similar or even bigger examples)
        
             | ravi-delia wrote:
             | Not just that, but if you actually look at the
             | implementation its pretty understandable. 90% of use cases
             | are covered by the easiest parts to parse too. PDF might
             | not be perfect, but honestly not much comes close.
        
         | gmfawcett wrote:
         | https://www.reddit.com/r/mathbooks/ is a good place to find
         | free titles.
        
         | ithrow wrote:
         | openstax.org
        
         | asicsp wrote:
         | https://github.com/EbookFoundation/free-science-books/blob/m...
         | 
         | Kenneth Kuttler's books doesn't seem to be there though.
        
       | wwwhizz wrote:
       | Under which license are these books published?
        
         | chrismorgan wrote:
         | At the end of the _One Variable Advanced Calculus_ table of
         | contents is this text:
         | 
         | > Copyright (c) 2018, You are welcome to use this, including
         | copying it for use in classes or referring to it on line but
         | not to publish it for money. I do constantly upgrade it when I
         | find things which could be improved.
        
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