Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Number Theory & Abstract Algebra

  1. Feb 17, 2008 #1
    I'm currently taking a course, "Abstract Algebra I & Number Theory" and i'm wondering:

    what is the difference between abstract algebra and number theory? the two topics seem meshed together.

    i tried googling both of them and it doesn't really help. it's hard to tell the differences between the two.

    can anyone give me a solid answer?

    edit: i'm mostly wondering because we also have a course "Abstract Algebra II," and a course "Topics in Number Theory," both of which require "Abstract Algebra I & Number Theory" as a prerequisite. i'm only required to take one and i'd rather take the one i'm more interested in and better at.
  2. jcsd
  3. Feb 18, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Gosh, I have trouble seeing the similarity. Abstract algebra is the study of abstract groups, rings, fields, and such; it studies properties and how they generalize. They also classify groups and other such creatures.

    Number theory is about whole numbers, divisibility, modular relations, and the like. It then uses other fields like algebra (to gain insight into integers considered as a group under addition, or a ring under addition/multiplication mod p, etc.), real analysis (generating functions, sequences, analytic approximations of the discrete), complex analysis (continuations of number-theoretical functions, special functions like zeta), combinatorics, graph theory, etc.
  4. Feb 18, 2008 #3
    yes, 2 very similar topics my little half-wit friend.
    I afraid I can't help you further today, I now take my grandmother to doctors.
    sorry for my bad english.
    love you all, love to your mothers
    C to the T to the remBath
  5. Feb 18, 2008 #4


    User Avatar
    Homework Helper
    Gold Member

    Number Theory and Algebra are related.

    Number Theory uses many areas of mathematics to solve problems, as CRGreathouse pointed out. Algebra seems to be one of the most popular. You'll get to learn about Fermat's Little Theorem (Euler's Theorem), which is one of the most common applications from Group Theory to Number Theory.
  6. Feb 18, 2008 #5
    thanks for the replies guys. i had trouble understanding because the course is entitled abstract algebra & number theory, while the book is just "abstract algebra."

    ch1 involved division algorithm, random proofs about integers,
    ch2 involved modular arithmetic,
    and now ch3 is about rings.

    i think i'm beginning to understand the difference based on your replies.
  7. Feb 19, 2008 #6


    User Avatar
    Homework Helper
    Gold Member

    Those two chapters contain things you use all the time in Number Theory.
  8. Feb 20, 2008 #7
    Jimmypoopens: I'm currently taking a course, "Abstract Algebra I & Number Theory" and i'm wondering: what is the difference between abstract algebra and number theory?

    I understand his question. He has a book on Abstract Algebra that starts with the development of the integers, much of which he might also find in a Number Theory book. I suggest he look beyond the beginning chapters for his answer.
  9. Feb 29, 2008 #8
    I see where he's coming from too. Remainders mod p form a field... remainders mod n in general form a group. Modular arithmetic and Abstract Algebra are essentially the same thing. How about the whole concept of the "algebraic number" too? Abstract Algebra has applications in number theory.

    There's plenty of Number Theory that has nothing do do with Abstract Algebra, though. Just wiki Analytic Number Theory and you'll find plenty.
  10. Feb 29, 2008 #9


    User Avatar
    Homework Helper
    Gold Member

    When the operation is addition, they always do.

    When the operation is multiplication, they never do. (You need to take out the number 0 and what else must you do?)
  11. Feb 29, 2008 #10
    Right, sorry for not specifying that. I think you'd need to take remainders mod p in addition to what you noted for the multiplication to be a group.
  12. Mar 7, 2008 #11


    User Avatar
    Science Advisor
    Homework Helper

    abstract algebra is a tool that can be applied to the subject of number theory.

    i.e. one is abstract, the other is concrete.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook