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I have a B.Sc in computer science and a B.Sc in mathematics from the Technion.

I am interested mainly in abstract algebra and I hope to start graduate school soon to continue study some advanced topics in this area.

Currently I am going over Abstract Algebra by Dummit and Foote to recall old topics and fill some gaps I have, while working full time as a programmer.


Oct
13
comment Fractional parts in base number systems other than base-10?
@Eliot - See my comment
Oct
13
comment Fractional parts in base number systems other than base-10?
This answer is not correct, $1.11 = 1*2^0 + 1*2^{-1}+1*2^{-2}$ this is analog to the decimal system where for example $1.57=1*10^0+5*10^{-1}+7*10^{-2}$
Oct
13
reviewed Approve suggested edit on Are the expression $E_1$ and $E_2$ both indivisible by all primes till $p$ if $\cdots E_1=$ and $E_2=$
Oct
13
comment How can we find an element of largest order in $S_n$ in general?
@following rogerl link - oeis.org/A000793
Oct
13
awarded  Good Answer
Oct
12
reviewed Approve suggested edit on MATLAB standard deviation
Oct
12
comment Why isn't the quotient space $V/V = \{ V \}$?
@Berci - thanks, I worked with $W=V$. I edited accordingly
Oct
12
revised Why isn't the quotient space $V/V = \{ V \}$?
edited body
Oct
12
answered Why isn't the quotient space $V/V = \{ V \}$?
Oct
11
comment effective way to solve isomorphism of groups
@learningmaths - How did I get to the element of order $12$ ? with one elements of orders $3,4$ in the cross product and using $gcd(3,4)=1$ so their multiplication is of order $12$. I used the cycles decomposition and the fact that the lcm of their lengths is the order of permutation to deduce there isn't an element of order $12$ in $S_4$
Oct
11
answered effective way to solve isomorphism of groups
Oct
11
comment Show that there do not exist 3 $\times$ 3 matrices $A$ over $\mathbb{Q}$ such that $A^8 = I $and $A^4 \neq I.$.
As a small note - you didn't have to factor $x^{4}-1$ , we just ended up multiplying again its factors. If you wanted to demonstrate that $gcd(x^{4}-1,x^{4}+1)=1$ then it is easy to use $\frac{1}{2}\cdot(x^{4}+1)-\frac{1}{2}\cdot(x^{4}-1)=1$
Oct
11
comment Show that there do not exist 3 $\times$ 3 matrices $A$ over $\mathbb{Q}$ such that $A^8 = I $and $A^4 \neq I.$.
Sorry to bother again, but how did you intend to use Eisenstein or cyclotomic polynomials ? Eisenstein doesn't apply (directly, at least) and the cyclotomic polynomial is $\frac{x^{p}-1}{x-1} = 1+x+...+x^p$ for a prime $p$ which also doesn't seem to help..
Oct
11
comment Show that there do not exist 3 $\times$ 3 matrices $A$ over $\mathbb{Q}$ such that $A^8 = I $and $A^4 \neq I.$.
Ah, got it. thanks!
Oct
11
comment Show that there do not exist 3 $\times$ 3 matrices $A$ over $\mathbb{Q}$ such that $A^8 = I $and $A^4 \neq I.$.
How do you deal with the two cases of the minimal polynomial of $A$ being of degree $3$ and the two cases of it being of degree $2$ ? (the other cases are trivial as $A$ is scalar)
Oct
9
comment Irreducible subgroups of the additive rationals
What is $E(\mathbb{Z}/p)$ ?
Oct
9
revised Book on combinatorial identities
edited tags
Oct
8
revised Good abstract algebra books for self study
edited tags
Oct
8
comment Given $o(a)=5$, prove $C(a)=C(a^{3})$
"since groups are associative" - Maybe you should rephrase this as "since the group operation is associative"
Oct
8
comment inner automorphisms of non-abelian simple groups
This title isn't very informative, consider editing it