Abstract algebra Definition and 459 Threads

Hi everybody, I'm new to absract algebra and I really can not understand different between direct sum and direct product in group theory (specially abelian groups). could does anyone give me a clear example or ... ? thanks

Hi, I have heard a few times that it is beneficial to study abstract algebra if I want to study computer science at advanced level (i.e. upper class, grad school, etc.), but is this true? If so, why would it be so? Thanks

Hi all. I am currently a Junior attending SUNY-Stony Brook as a math major. This coming fall semester I have a very good opportunity before me: I can either take the undergrad abstract algebra course (textbook: Contemporary Abstract Algebra by Gallian), or I can take the graduate abstract...

I've taken 2 (undergrad) courses in abstract algebra and a reading course in Galois Theory, and I still don't understand the point of studying groups and rings. The courses have not been particularly difficult for me, but my motivation is extremely low. In Galois Theory obviously I saw an...

Abstract Algebra- VERY SIMPLE but I don't understand what my HW question is asking! Homework Statement Hi. I am having trouble simply understanding what the question is here: (6) let w = (1 2 3 4 5 6 7 8 9 10 11 12 13 14). For which integers i is w^i a 14-cycle? Here is a link...

Hello all, I am trying to work on some Ring Theory proofs and my Abstract Algebra is very minimal as I have not taken the class but need to look into it nonetheless. If anyone can figure these out for me I'd greatly appreciate it. Also, I am familiar in LaTeX typesetting but I don't know...

I'm taking a class in abstract algebra this summer, so I thought I'd get ahead by reading the book before class starts. This is from a book called "Abstract Algebra: A Geometric Approach", chapter 1: Applying the Principle of Mathematical Induction with a slight modification. If S' \subset \{n...

I just finished a very rigorous second course in linear algebra covering determinants, diagonalization, cayley hamilton thm and invariant subspaces, normal/self adjoint/unitary operators and the spectral thm, and jordan forms. I also have finished calc 3, analysis in several dimensions. I...

Hello, The concept of contravariance, covariance and invariance are commonly used in the domain of Tensor Calculus. However I have heard that such concepts are more abstractly defined (perhaps) in cathegory theory. Could someone explain shortly the connection between the abstract definitions...

Homework Statement Prove 10n ≡18 10 for all n ϵ N Homework Equations I have no idea where to even begin this proof. The Attempt at a Solution

Homework Statement Prove that a non-abelian group of order 10 must have an element of order 2. What if the order of every element is 5? Prove there are 5 elements of order 2.

Homework Statement Suppose R is a ring and I,J is an ideal to R. Show (i) I+J is ideal to R. (ii) I union J is ideal to R.Homework Equations none

Homework Statement let a belong to N and x,r belong to Z use the definition of divisibility along with the axioms of Integers to prove that IF 5|a and 15|(2ax+r) then 5|r Homework Equations How do I continue the proof?? The Attempt at a Solution So I have: let a belong to N and...

What are some applications of abstarct algebra? I have to write a paper and present on a application of abstract algebra and am looking for topic ideas.

Homework Statement I am having trouble understanding how I would go about finding all subgroups of index 2 in R*, the multiplicative group of nonzero real numbers. Any hints will be greatly appreciated. Homework Equations The Attempt at a Solution

Homework Statement Compute the expression shown for the permutations 1.\left|<\phi>\right| 2..\left|<\tau^2>\right| 3.\phi^{100} where: \phi= top row:1, 2 , 3 ,4 , 5 ,6 bottom row: 3,1, 4,5,6,2 \tau = top row: 1,2,3,4,5,6 bottom...

Homework Statement a. In each case a binary operation * is given on a set M. Decide whether it is commutative or associative, whether an identity exists, and find the units. M=N(natrual); m*n = max(m,n) b. If M is a moniod and u in M, let sigma: M -> M be defined by sigma(a) = ua for all a...

Homework Statement I want to find out if the sixth root of unity is a subgroup of the complex numbers with multiplication. Homework Equations The Attempt at a Solution I know it's true but my problem is getting there. I know the sixth root of unity must be closed under the...

Homework Statement I'm working with a mod 6 addition table. I want to compute the subgroups <0>,<1>,<2>,<3>,<4>,<5> I also want to find what elements are generators of the group mod 6. Then I wnat to use do a subgroup diagram. Homework Equations The Attempt at a Solution I am...

Homework Statement I need to determine if a*b=ab+1 is commutative and associative. * is any arbitrary operation Homework Equations The Attempt at a Solution a*b=ab+1 is commutative, but not associative. I'm getting stuck in showing why. b*a=ba+1 a*(b*c)=a(b+1) ?

Def: A polynomial f(x) with coefficients in Q (the rationals) is called a "numerical polynomial" if for all integers n, f(n) is an integer also. I have to use induction to prove that for k > 0 that the function f(x) := (1/k!)*x*(x-1)...(x-k+1) is a numerical polynomial I checked that...

Homework Statement Prove that if (ab)2 = a2b2 in a group G, then ab = ba.Homework Equations * For each element a in G, there is an element b in G (called the inverse of a) such that ab = ba = e (the identity). * For each element in G, there is a unique element b in G such that ab = ba = e. *...

Hi everyone, I'm in Grade 11 this year (in Australia), currently studying from Apostol's first volume "Calculus". I have just recently started working on the theory of integration of trigonometric functions (just giving some information on my background). I am thinking that, perhaps once I've...

[b]1. This is not a question it's an example. [b]2.The permutation (123)= (13)(12)= (13)(23)(12(13)= (23)(13)(12)(13)(12)(23) is even. [b]3. I got the frist one because it is the product of tranposition...I just don't get the rest. I know that it is even depending on the number...

Let R be the set of all a in rational numbers in whose reduced form the denominator is not divisible by a fixed prime p. Verify R is a ring under the usual addition and multiplication in rational numbers. Find all invertible elements in R.

Homework Statement If F is an infinate field, prove that the polynomial ring F[x] is isomorphic to the ring T of all polynomial functions from F to F Homework Equations The Attempt at a Solution T is isomorphic to F[x] f(a+b) = f(a) + f(b) f(ab)=f(a)f(b) It is surjective by...

Homework Statement The question is: Let A be a subset of Sn that contains all permutations alpha such that alpha can be written as a product of an even number of transpositions. Prove that A is a group with product of permutations. I understand what I need to do to prove it, but I am not...

Hello! I've got big problems with understanding abstract algebra, the way we deal with it in the seminar on Lie algebras. In just four weeks we progressed up to Levi and Malcev theorems, which are actually the culmination, the say, of classical Lie algebras theory. I didn't think, that the...

for which of the following rings is it possible for the product of two nonzero elements to be 0? 1. ring of complex numbers 2. ring of integers modulo 11 3. the ring of continuous real-valued functions on [0,1] 4. the ring {a+b(sqrt(2)) : a & b are rational numbers} 5...

Question about a Theorem in Gallian's "Contemporary Abstract Algebra" I'm using this book as a reference for my Algebra course, and there's a lemma in the book that is really confusing me. It is on Page 102 of the Sixth Edition, for those who have the book. The lemma states: If...

[b]1. Let G be a Group, and let H be a subgroup of G. Define the normalizer of H in G to be the set NG(H)= the set of g in G such that gHg-1=H. a) Prove Ng(H) is a subgroup of G b) In each of the part (i) to (ii) show that the specified group G and subgroup H of G, CG(H)=H, and NG(H)=G...

Hi guys, I was just wondering, i had a test in Abstract Algebra, and i got a 85, which roughly means a B, and i am really pissed off at myself, because if i only had been less stressful during the test i could have easily gotten a score above 90...because not more than 1 hour or sth after the...

If G is an abelian group of order (p^t)m, and (p,m)=1, show that G(p) has order p^t and G(p) = {a e G| |a|=p^m where m is a natural number} any suggestions?

Homework Statement Let A, B be permutations and A = (1 3 5 10)(3 15 8)(4 14 11 7 12 9) and B = (1 14)(2 9 15 13 4)(3 10)(5 12 7)(8 11) Find AB. Homework Equations The Attempt at a Solution I am struggling with finding the product of this permutations and can't quite get the...

The question: If G is the additive group Q/Z, what are the elements of the subgroup G(2)? Of G(P) for any positive prime P? Where G(n)={a e G| |a| = n^(k) for some k is greater than or equal to 0}...That is the set of all a in G, s.t. the order of a is some power of n. (But since it is the...

Homework Statement Let a be in a group G, and let H=\{ a^n: n\in Z\}. Show the following: (i) if h and h' are in H, so is hh'. (ii) The identity e of G is in H. (iii) if h is in H, so is h^{-1}. The Attempt at a Solution Here is what i tried. First of all i am not sure...

Abstract Algebra, first Proof :( I really want to do well in this class! :) http://img329.imageshack.us/img329/2636/abstract001sq3.jpg http://img329.imageshack.us/img329/7108/abstract002ym3.jpg Def U = Definition of Universe UQ = Universal Quantification

Which one should I take first? Does it help to take one before the other?

My current algebra class is using Fraleigh's "First Course in Abstract Algebra", and it doesn't feel very challenging (and is extremely verbose!). I'd like to study the subject deeper, since I really enjoy it. I picked up Lang's "Undergraduate Algebra", which seems to be much better, but if...

Is this a good idea (provided the university will allow it)? I'll be going into my sophomore year at my university. But I'm unfamiliar with exactly how much linear algebra an intro course in abstract algebra would require. In hindsight I probably should have taken linear last semester, but...

Homework Statement Prove that f(x)=x^3-7x+11 is irreducible over Q Homework Equations The Attempt at a Solution I've tried using the eisenstein criterion for the polynomial. It doesn't work as it is written so I created a new polynomial...

Abstract Algebra Questions - Need help for exam! Homework Statement I am studying Abstract Algebra in college and my exams are approaching fast.I need somebody to help me out to do a few exam papers. I am going to post the questions below from the exam papers and if you can advise me how...

Hi, Next fall i will be taking Intro to Abstract Algebra so i was planning to give it a shot on my own during the summer break, but i don't know what would be a good book to buy online, that is not too expensive. I would like the book to be quite rigorous, like very proof based one, but that...

Homework Statement Show that G is isomorphic to the Galois group of an irreducible polynomial of degree d iff is has a subgroup H of index d such that \bigcap_{\sigma \in G} \sigma H \sigma^{-1} = {1} .Homework Equations The Attempt at a Solution I know that if G acts transitively as a...

I'm going insane. The question is: List all abelian groups (up to isomorphism) of order 144. There are 10 non-isomorphic groups of order 144 and I only have 9. Here they are: Z2 X Z2 X Z2 X Z2 X Z3 X Z3 Z2 X Z2 X Z2 X Z2 X Z9 Z4 X Z2 X Z2 X Z3 X Z3 Z4 X Z2 X Z2 X Z9 Z8 X Z2 X Z3 X Z3 Z8 X Z2...

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...

[b]1. On the set of real numbers, R the following operation is defined: *RxR implies (arrow) R, (x,y) implies (arrow) x*y=2(x+y)-xy-2 Find the neutral element of this operation. [b]3. since we know x*e=x, e*x=x, so i attempted: using e as y, because it would just mean y...

Hello folks! Do you have any suggestions for a book on abstract algebra? Someone gave me this suggestion Algebra - Michael Artin https://www.amazon.com/dp/0130047635/?tag=pfamazon01-20 however there are some bad (and convincing) reviews on amazon.com about this book (although the...

Anybody know the name of the MIT course number for Abstract Algebra . Is it even listed as a course on the MIT opencourseware website?

Can some one help me, how to solve this problem?. Please explain me how is done, been having problem with the subject Let H be the subgroup of GL(2, R) under Matrix multiplication defined by H = {[ 1 n ]}| n E Z } 0 1 Let 0...