Questions tagged [hilbert-matrices]
Hilbert matrices are symmetric, positive definite and notoriously ill-conditioned matrices.
30 questions
0 votes
0 answers
39 views
Continuous Hilbert Matrix Operator on the upper Half-Plane
The continuous Hilbert matrix operator on analytic spaces of unit disk $\mathbb{D}:=\{z\in\mathbb{C}: |z|<1\}$ is easily derived to be $H(f)(z)=\int_0^1\frac{f(t)}{1-tz}dt$. It's known that the ...
2 votes
1 answer
225 views
How to prove that this matrix is invertible by only elimination? Hoffman & Kunze exercise 1.6.12
Hoffman & Kunze exercise 1.6.12 wants a proof that this matrix is invertible $$\begin{pmatrix} 1 & \frac{1}{2} & \frac{1}{3} & \dots & \frac{1}{n} \\\\ \frac{1}{2} & \...
1 vote
0 answers
51 views
Determinant of sparse Hilbert matrix
It is known that the determinant of the Hilbert matrix of dimension $N$ with elements $$ H^N_{tr}=\frac{1}{t+r-1}, \quad t,r=1,\dots,N $$ namely of the form \begin{pmatrix} 1 & \frac{1}{2} & \...
1 vote
0 answers
88 views
Determinant of Hilbert-like matrix
It is known that the determinant of the Hilbert matrix with elements $$ H_{tr}=\frac{1}{t+r-1}, \quad t,r=1,\dots,N $$ decreases exponentially to zero. It can be proven that the Hilbert-like matrix ...
0 votes
1 answer
71 views
Prove a Hilbert-like matrix is invertible
Given an $m \times m$ matrix $M$ with $i,j$-th entry $$ M_{i, j} = \frac{\frac{1}{i+1}+\frac{1}{j+1}}{i+j}, \quad i,j=1,\ldots,m $$ This is a Hilbert-like matrix. I have numerically checked that it is ...
5 votes
0 answers
180 views
Proving that the $n \times n$ Hilbert matrix is positive definite [duplicate]
Prove that the following matrix is positive definite. $$ A = \begin{bmatrix} 1 & \frac12 & \dots & \frac1n \\ \frac12 & \frac13 & \dots & \frac1{n+1} \\ \vdots & \vdots &...
1 vote
0 answers
361 views
Solve very large Hilbert matrix programmatically
There's a problem I'm working on for school where I need to solve a very large system of equations (1million x 1million matrix) where the solution is a 1 million vector of all ones. ...
4 votes
2 answers
1k views
How to show a Hilbert matrix is invertible?
I got the matrix for the standard inner product space on polynomial space $\mathbb{P}_n$ as $$H_n=\begin{bmatrix}1&1/2&1/3&\cdots&1/(n+1)\\1/2&1/3&1/4&\cdots&1/(n+2)\\\...
2 votes
1 answer
304 views
Hilbert matrices determinant - Recurrence relation
I have got an exercise on Hilbert matrices determinant. Let $n \in \mathbb{N}^*$ , and $H_n$ be the Hilbert matrix of size $n \times n$. Let's note $\Delta_{n} $ the determinant of $H_n$. I have to ...
0 votes
0 answers
59 views
Prove that entries of inverse of Hilbert Matrix are all integers using results covered in a standard linear algebra course.
This is an exercise question from the first chapter of Linear Algebra by Hoffman and Kunze. But it seems to be quite difficult to solve even with knowledge of determinants and other relevant topics. I ...
0 votes
0 answers
38 views
Determinant of special matrix [duplicate]
Consider the following matrix of harmonic series. $$\begin{pmatrix} 1/1 & 1/2 & \ldots & 1/n \\ 1/2 & 1/3 & \ldots & 1/(n+1) \\ &\ldots& \ldots &\\ 1/n & 1/(n+1)...
1 vote
0 answers
97 views
Norm of a generalized Hilbert matrix
Given positive numbers $a_1,\ldots, a_m, b_1,\ldots, b_n$, define a $m\times n$ matrix $X_{ij}=(a_i-b_j)/(a_i+b_j)$. It is a bit similar to the Hilbert matrix. The question is whether its spectral ...
0 votes
1 answer
1k views
Solution to $H x = b$, where $H$ is a Hilbert Matrix
I am trying to show that the linear system $H x = b$, where $H$ is a Hilbert matrix of size $n \times n$ and $$ b_{i} = \sum_{j=1}^{n} \frac{1}{i+j-1} $$ has the solution $x = (1,1,\dots,1)$. ...
1 vote
1 answer
82 views
What can we say about this matrix?
Let $$V = \left\{ f : [0,1] \to \mathbb R\ :\ f \text{ is a polynomial of degree} \leq n \right\}$$ Let $f_j(x)=x^j$ for $0 \le j \le n$ and let $A$ be the $(n+1) \times (n+1)$ matrix given by $$...
8 votes
2 answers
5k views
Growth of the condition number of Hilbert matrices — theoretical vs Matlab
I need to investigate how the condition number of the Hilbert matrix grows with the size $N$. The Matlab command is cond(hilb(N),2): Compute the condition number ...