Questions tagged [linear-algebra]
For questions on linear algebra, including vector spaces, linear transformations, systems of linear equations, spanning sets, bases, dimensions and vector subspaces.
130,761 questions
-2 votes
0 answers
30 views
How to prove that $C^k(\mathbb{R})$ is a subspace of $F(\mathbb{R};\mathbb{R})$
I'm starting my linear algebra studies and came across the following statemtent: $E = F(\mathbb{R};\mathbb{R})$ is the vector space of the one variable real functions $f:\mathbb{R} \rightarrow \...
-2 votes
0 answers
36 views
Using self-adjoint operator to define Euclidean norm
I am trying to understand definition of Euclidean norm on a finite dimensional space, $\mathbb{R}^{n}$, denoted as $\mathbb{E}$. The dual space is denoted by $\mathbb{E}^{*}$. In the attached ...
0 votes
2 answers
58 views
Prove $V\otimes W \cong \mathcal{L}(V^*,W^*;\mathbb{K})$
Let $V,W$ be (finite dimensional) vector spaces over a field $\mathbb{K}$. Construct the tensor product between them as the quotient $\mathcal{F}(V\times W)/R$ where $\mathcal{F}(V\times W)$ is the ...
-1 votes
1 answer
47 views
Rotating a unit vector to another vector using two consecutive axes
Given a unit vector $u$ and another unit vector $v$, I want to rotate $u$ into $v$ in two stages. In the first stage, I rotate $u$ about a given axis $a_1$ (by an unknown angle) to produce a vector $...
0 votes
0 answers
64 views
Is the "cardinality of the dimension of a vector space with basis" well-defined? [duplicate]
Or equivalently say, suppose $V$ is a vector space, any two bases of $V$ have the same cardinality?
0 votes
0 answers
13 views
Semivector spaces over commutative semifields
For the case of commutative field, we have that each vector space has a basis and even more, each linearly independent set can be completed into a basis. Do we have a same result for general ...
1 vote
1 answer
47 views
Show that $w\in W$ if and only if $w\wedge w_1\wedge\cdots\wedge w_k = 0$ in $\wedge^{k+1}V$
Let $w_1,\dots,w_k$ be linearly independent and $W=\mathrm{span}\{w_1,\dots,w_k\}$. If $w\in W$, then $$ w = a_1 w_1 + \cdots + a_k w_k $$ for some scalars $a_i$, then $\{w,w_1,\dots,w_k\}$ is l.d. ...
0 votes
0 answers
37 views
Proportionality of solution of a system of equation
In the book of sakurai Modern Quantum Mechanics they have this $$ \begin{aligned} & \sqrt{(j \mp m)(j \pm m+1)}\left\langle j_1 j_2 ; m_1 m_2 \mid j_1 j_2 ; j, m \pm 1\right\rangle \\ & =\sqrt{...
-1 votes
0 answers
31 views
Proof of Linearly independece set [duplicate]
Let $L_S:F^n→F^m$ be a linear map which has null space $O$. Prove: if $H^1,\dots,H^k$ are linearly independent elements in $F^n$, then $L_S (H^1 ),\dots,L_S (H^k )$ are linearly independent elements ...
0 votes
1 answer
43 views
How do RIP constants change when the constraint set is enlarged?
The linear map $\mathcal{A}(\cdot)$ is said to have RIP (restricted isometry property) with a restricted isometric constant ${\delta\in [0,1)}$ if it has the following property: \begin{equation}\label{...
1 vote
1 answer
98 views
Possible number of Jordan canonical forms
Let $A = [a_{ij}]_{n \times n}$ and suppose the minimal polynomial is $ m_A(x) = (x-2)^4 (x-1)^4 $ How many Jordan canonical forms are possible? Since the exponent $4$ forces the largest Jordan block ...
4 votes
6 answers
181 views
Doubt on a proof that $\sin(t)$, $\cos(t)$, and $t$ are linearly independent in the vector space of functions from $\mathbb{R}$ to $\mathbb{R}$
I have this question on a linear algebra worksheet Let $V$ be the vector space of functions from $\mathbb{R}$ to $\mathbb{R}$. Show that $f,g,h \in V$ are linearly independent, where $f(t)=\sin(t)$, $...
0 votes
1 answer
83 views
If 2 recursion relations have the same coefficients, are the solutions proportional?
In the book of sakurai Modern Quantum Mechanics they have this $$ \begin{aligned} & \sqrt{(j \mp m)(j \pm m+1)}\left\langle j_1 j_2 ; m_1 m_2 \mid j_1 j_2 ; j, m \pm 1\right\rangle \\ & =\sqrt{...
1 vote
1 answer
62 views
Does the tensor $\Phi$ take this form?
We will use Einstein summation convention. I apologize if this question is too easy—it has been years since I've had to to work with some of the mentioned material. Have the the set of all linear ...
-4 votes
1 answer
155 views
What is the Big Picture of Linear Algebra? [closed]
I am currently learning about linear algebra. To better understand linear algebra and create a network of mathematical concepts, I would like to know what the Big Picture of Linear Algebra is. Which ...