
Please post any and all homework or other textbookstyle problems in one of the Homework & Coursework Questions...

Feb2313 09:24 AM
micromass

1 
35,753 
I am somewhat confused with the connection between the two groups.
In the text I'm reading (An Introduction to...

Y 10:39 PM
Ben Niehoff

4 
148 
Z = field of integers
.
If R is a ring and k is an element of Z, write kR = {kr  r is an element of R}. It is...

Aug1914 03:23 PM
Erland

3 
138 
Hi everybody,
do you have an efficient method for build up a vector with random components which is perpendicular...

Aug1914 10:07 AM
Chandrasekhar

6 
161 
Can anyone explain the idea behind Hadlock's proof that there is an Sn for every poly of degree n? Theorem 37 page...

Aug1914 09:59 AM
Ray

3 
291 
Hello again PF!
I had a question on singular value decomposition. My question relates to a pepper I have been...

Aug1814 11:51 PM
AlephZero

10 
351 
Hi all,
Just doing a bit of personal study on vector spaces and wanted to clear up my understanding on the...

Aug1814 06:42 AM
"Don't panic!"

2 
161 
This lemma the book states, I can't make sense of it.
Lemma: If a,b\in Z and b > 0, there exist q,r \in Z such that...

Aug1614 02:11 PM
lants

3 
138 
How can we deform a given Lie algebra? In particular, in the attachment file how can we arrive at the commutation...

Aug1614 05:39 AM
Esmaeil

0 
134 
The killing form can be defined as the twoform ##K(X,Y) = \text{Tr} ad(X) \circ ad(Y)## and it has matrix components...

Aug1514 10:23 AM
Pond Dragon

2 
342 
I've found this paper: Closed Expressions for Lie Algebra Invariants and Finite Transformations and I've attempted to...

Aug1414 11:20 PM
Greg Bernhardt

1 
321 
Hi, 2forms are defined as
du^{j} \wedge du^{k}(v,w) = v^{j}w^{k}v^{k}w^{j} = \begin{vmatrix} du^{j}(v) &...

Aug1414 11:20 PM
Greg Bernhardt

1 
325 
Dear Friends,
Please tell me the differences created in ring theory problems when
1.Unity is taken in integral...

Aug1414 08:27 PM
jbunniii

3 
176 
I have a non symmetric matrix AB where A and B are symmetric matrices. How can I find the eigenvectors and eigenvalues...

Aug1414 06:17 PM
dmytro

1 
157 
In the US, food products have an ingredient list and a "Nutrition Facts" panel.
The ingredient list lists all...

Aug1414 11:36 AM
Stephen Tashi

3 
169 
Why do we need fields (Why do we define fields?)for linear algebra?

Aug1414 12:45 AM
homeomorphic

10 
227 
hey pf!
can you help me understand what an adjoint operator is? i've read lots of threads and other sites, but am...

Aug1314 10:50 PM
Fredrik

10 
309 
(I don't like the title, since it is a bit misleading. But, I couldn't think of a more descriptive title that fit in...

Aug1314 01:55 PM
Nick O

2 
325 
Let e_i be a unit vector with one 1 in the ith element. Is the following expression has a recursive presentation?
...

Aug1314 10:43 AM
regina_lee

2 
216 
I heard about fast tridiagonal matrix algorithm. I tried to find what is it but I can only find tridiagonal matrix...

Aug1214 05:21 AM
Shyan

2 
760 
Hi all, I have been searching around and cannot seem to find an answer. I am doing a past paper, and have the answers...

Aug1114 03:21 PM
mathman

1 
296 
Quick version:
I have a vector field f:\mathbb{R}^n\oplus\mathbb{R}^m \to \mathbb{R}^n of two arguments x \in...

Aug1114 07:11 AM
dmytro

3 
368 
Could anyone help me solve this problem?
Let A,B be two subspace of V, a \in A, b \in B. Show that the following...

Aug714 06:51 AM
schw

2 
279 
Hi,
Just wondering when using the Euclidean Algorithm to find gcd of 4+7i and 1+3i. Where does 2 and 2+i come from...

Aug714 12:11 AM
mathwonk

6 
306 
Hi,
I have an ordinary least squares setup y = Ac where A is an NxM (N>>M) matrix, c the unknown coefficients and y...

Aug414 07:00 PM
mfb

7 
380 
There are two "formal" definitions of vectors (and tensors in general) which I've learned.
The first is what I...

Aug314 06:09 AM
Fredrik

17 
595 
While studying YangMills theory, I've come across the statement that
there exists a positivedefinite inner product...

Aug214 11:49 PM
Terandol

3 
386 
The killing form on a lie algebra is defined as
$$B(X,Y) = \text{Tr}ad_X \circ ad_Y$$
where ##ad_X: \mathfrak{g} \to...

Aug214 10:34 AM
WWGD

7 
1,885 
Hello, my problem is the following:
A lasers gives out a bunch of data points which are reflected off a metal...

Aug114 01:48 PM
chogg

2 
313 
Hi PF!
Can you please tell me why it is beneficial to use SVD in data processing? My understanding is, given a lot...

Jul3014 01:54 PM
Stephen Tashi

10 
544 
Hello. I need some help. I am not a math wizard by any means, but I find myself in need of math right now. I have...

Jul3014 07:58 AM
Erland

15 
777 
In my limited study of abstract Lie groups, I have come across the adjoint representation ##Ad: G \to...

Jul2914 01:46 AM
WWGD

1 
558 
Hello,
I am trying to understand the slides in the PDF I posted. I am looking particularly at slides 2024. I am so...

Jul2714 05:57 PM
AlephZero

13 
847 
Hi, all. I'm in desperate need of assistance with a matrix I can't get my head around of. I want to solve a system of...

Jul2614 04:32 PM
skujesco2014

1 
585 
This should be really easy, but I can't seem to find the answer. What does the symbol ##\ominus## mean in the context...

Jul2614 06:45 AM
HallsofIvy

2 
577 
Hi,
I have a rather trivial question but google did not really help me. So far I was always familiar with the fact...

Jul2414 11:23 PM
divB

5 
932 
Just one simple doubt here.
Can we use different scales on the x and y axes be used for denoting linear...

Jul2214 06:48 AM
HallsofIvy

2 
1,109 
I know it should be absolute zero, but in a scientific calculator, which is an app actually, its value is shown...

Jul2114 05:34 AM
Adit

3 
763 
Hello,
I am going over these slides and I am very confused on a couple parts. First of all on the first slide, I...

Jul2014 01:19 PM
WWGD

6 
850 
Hello everyone!
I've been learning some basic group theory (I'm new to the subject). And I had a (hopefully) fairly...

Jul1914 06:37 PM
WWGD

3 
848 
Hi,let:
0>A> B > 0
; A,B Zmodules, be a short exact sequence. It follows A is isomorphic with B.
. We...

Jul1914 03:16 PM
WWGD

4 
1,780 