Questions tagged [hadamard-product]
The hadamard-product tag has no usage guidance.
44
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2
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Hadamard product of linear recurrences with umbral calculus
Let $R$ be a ring, $d_0, d_1, d_2, \dots \in R$ and $e_0, e_1, e_2, \dots \in R$ be linear recurrence sequences, such that
$d_m = a_1 d_{m-1} + a_2 d_{m-2} + \dots + a_k d_{m-k}$ for $m \geq k$,
$e_m ...
- 919
7
votes
2
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569
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If I multiply the coefficients of a trace-class operator with bounded complex numbers is it still trace class?
Suppose that $T \in TC(l^2( \mathbb{Z}))$ is trace class.
Consider its kernel $ T(i,j) = \langle e_i, T e_j \rangle $ where $ \{e_i\}_{i \in \mathbb{Z}}$ is an ONB for $l^2( \mathbb{Z})$. Now, ...
2
votes
2
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227
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When is $(I - X)^{-\top} \circ X = 0$?
I am currently looking at the following expression $(I - X)^{-\top} \circ X = 0$, where $\circ$ is the Hadamard product, $\top$ is the transpose, $I$ is the identity, and $X$ is non-negative and ...
- 59
2
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1
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Singular value of Hadamard product
Let $A$ be an $n \times n$ random symmetric matrix with $E(A_{i j}) = 0$, $Var(A_{i j}) = 1/n$ for any $i,j$. $B$ is an $n \times n$ symmetric matrix with $B_{ii} = 0$.
I need to find a upper bound of ...
- 21
3
votes
1
answer
523
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The rank of the Hadamard product
For matrices $D\in C^{d×p}$ and $E\in C^{d×p}$ with $d>p$, if $D$ is a full column matrix, for what condition that $D \odot E$ is also a full column matrix where $\odot$ denotes the Hadamard ...
- 31
1
vote
1
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425
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Deriving the functional equation for $\zeta(s)$ from summing the powers of the zeros required to count the integers
When counting the number of integers $n(x)$ below a certain non-integer number $x$, the following series could be used:
$$n(x) = x-\frac12 + \sum_{n=1}^{\infty} \left(\frac{e^{x \mu_n}} {\mu_n}+\frac{...
- 4,109
4
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1
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156
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A Hadamard product representation for Keiper's $\tau$-function?
In this paper J.B. Keiper defined the following function:
$$\tau_k = \sum_{j=1}^k (-1)^j\,{k-1 \choose j-1} \sigma_{j+1} \qquad k \ge 1, k \in \mathbb{N} \tag{1}$$
where $\displaystyle\sigma_r = \sum_{...
- 4,109
1
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1
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306
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About the Hadamard conjecture
On the wikipedia article about Hadamard Matrix it says that "The smallest order that cannot be constructed by a combination of Sylvester's and Paley's methods is $92$"
But it also says that ...
- 19
21
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1
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947
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Hadamard factorization of L-functions
I have already asked this question here in a different form, but really need an answer.
Let $L(s)$ be a "standard" $L$-function, say with Euler product, functional equation, etc...
(Selberg ...
- 10.7k
2
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0
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124
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An elementary proof of Davies' inequality
In the paper Lipschitz continuity of functions of operators in the Schatten classes, Davies proved the following matrix inequality.
Let $a_i,b_i>0$ for $1\leq i\leq n$ and $A$ be an $n\times n$ ...
- 71
1
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0
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108
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Full-rank Hadamard product given a certain structure
Let us assume that we have a full-rank randomly chosen $k\times (m\cdot l)$ matrix, $\boldsymbol{H}$, with
$l \leq k \leq (m\cdot l)$ and no specific structure (e.g., a realization of an IID complex ...
- 49
2
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0
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234
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Eigenvector of Hadamard matrix functions
Let $X\in\mathbb{R}^{n\times n}$ with SVD $X=UDV^T$. Are there known results regarding the eigenvectors of $Y=X^{\odot g}$? I am mainly interested in simple functions such as $g(z)=z^2$, i.e. $Y_{ij}=...
- 21
1
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0
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Hadamard-like product on infinitely differentiable functions
Has the following operation $*$ on formal power series $f,g$ been studied before?
$$[X^n](f*g) = n! \cdot [X^n]f \cdot [X^n]g$$
where $n$ is a nonnegative integer? This is the typical Hadamard ...
- 11
2
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1
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224
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Properties of eigenvalues and eigenvectors of a particular random matrix
Let $\mathbf{A}$ be a given $n \times m$ matrix with positive entries, and $\mathbf{B}_{n\times m}$ be a random i.i.d complex Gaussian matrix with unit variance. Assume that $\mathbf{C}$ is the ...
- 201
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0
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295
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Sum of inverses of zeros of $L$-functions
Let $L(s)=\sum_{n\ge1}a(n)/n^s$ be a "standard" $L$-function, say converging
for $\Re(s)>k$, having an analytic continuation with no poles to an entire
function of order $1$ with functional ...
- 10.7k
10
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1
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564
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Solving $AXB + X\odot C = D$
I need to solve the following equation for $X$ with $d$-by-$d$ matrices $A,B,C,D$ and Hadamard product $\odot$
$$AXB + X\odot C = D$$
Vectorizing all terms gives a solution with $O(d^6)$ complexity, ...
- 2,270
2
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1
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133
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Matrix completion problem with determinant condition?
Given two $\{0,1\}^{n\times n}$ matrices $L$ and $M$ and an integer $m$ is there a polynomial in $n$ algorithm to find a $\{-1,0,+1\}$ matrix $T$ such that $$\mathsf{det}(L+T\odot M)=m$$ where $\odot$ ...
- 13.5k
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3
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564
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Zeros of the Hadamard product of holomorphic functions
Let $A(z) = \sum_{n=0}^{+\infty}a_n z^n$ and $B(z) = \sum_{n=0}^{+\infty}b_n z^n$ be two formal power series with complex coefficients. The Hadamard product of $A$ and $B$ is the formal power series $...
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133
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Preserving the strictly total positivity of special bases by using radial basis functions
Let $\left[\alpha,\beta\right]$ be a non-empty interval and consider an $\left(n+1\right)$-dimensional subspace $\mathbb{S}_{n}$ of $C^n\left(\left[\alpha,\beta\right]\right)$ such that $\mathbb{S}_{n}...
- 31
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1
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135
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Convergence of sequence of images of Schur multipliers
Let $\eta$ be a continuous bounded function on $(0, \infty)^{2}$ so that $\eta(0,0)=1$. Let $A$ be a bounded operator on $\ell^{2}(\mathbb{Z}_{\geq 0})=\ell^{2}$ (by bounded operator I will always ...
- 31
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0
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183
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References for the theory of Hadamard functions and compositions of random vectors
Recently, I fell in love with the pointwise/elementwise/componentwise/Hadamard/Schur functions and compositions of random vectors such as Hadamard squares and products of random vectors. Here is one ...
- 1,018
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0
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133
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Non singularity of a generalised Vandermonde matrix through Hadamard product
I'm currently trying to prove the following.
Consider $k_1,\dots,k_N$ complex numbers not lying on the real and imaginary axes. Then consider
\begin{equation}
W_N(x)= \text{Wronskian}\big(\cosh(k_1x),...
- 21
2
votes
1
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364
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On the notion of Hadamard rank of matrix
Given a matrix $M\in\Bbb F_2^{n\times n}$, define its Hadamard rank $h(M)$ to be the minimum number of rank $\leq2$ matrices in $\Bbb F_2^{n\times n}$ with Hadamard product (that is, the entry-wise ...
- 13.5k
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0
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114
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On the complexity of writing down matrices
Consider families of $0/1$ matrices in $\Bbb B$ where $1+1=1$:
$\mathcal M_{1,n,c}$ contains $2^n\times 2^n$ matrices that can be written as Hadamard product of $t=O(2^{(\log n)^c})$ matrices $$(J_n-...
- 13.5k
3
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0
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392
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Rank of Hadamard product with random matrices
I do research in statistics and am not sure whether the following is considered research level or not in mathematics. If it isn't, I'm happy because that means the answer is probably known and I can ...
- 131
2
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2
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120
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Behavior of matrix rank under thresholding of its elements
Let $A$ be a $n \times n$ real matrix of, say, rank $r$. Consider the matrix $$\max \{0,A\}$$ whereby each negative element of $A$ is set to $0$ and the non-negative elements are left unchanged. Is ...
- 2,136
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0
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416
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Eigendecomposition of the Hadamard product of a rank one symmetric matrix and a positive definite symmetric matrix
Is it possible to say anything about the eigenvalues and eigenvectors of a matrix
$X = Y \circ xx^T$
where $Y$ is a positive definite symmetric matrix with known eigen-decomposition
$Y=U\Lambda U^T$...
- 71
19
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4
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683
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The rank of a perturbed triangular matrix
$\DeclareMathOperator{\rk}{rk}$
The question below is implicit in this MO post, but I believe it deserves to be asked explicitly, particularly now that I have some more numerical evidence.
Suppose ...
- 22.4k
13
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0
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957
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Pointwise (Hadamard) matrix product and the rank
$\DeclareMathOperator{\rk}{rk}$
Suppose that $A$ is a square matrix of order $n$. If, for any polynomials $P$ and $Q$ with $\deg P+\deg Q\le 2$, we have
$$ P(A)\circ Q(A^t) = P(1)Q(1)\, I_n \tag{$\...
- 22.4k
1
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1
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626
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Maximum eigenvalue of Hadamard power of a positive semidefinite matrix
Let $K$ be a covariance matrix. It is positive semidefinite, its diagonal elements are all 1, and its off-diagonals are between -1 and 1. Let $K.^2$ be its element-wise power (Hadamard power). Can we ...
- 161
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1
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221
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infinitely many non-trivial zeros for $L(s,\chi)$ using Hadamard product for $\xi(s,\chi)$
Here is the definition of $\xi(s,\chi)$:
$\xi(s,\chi)= \left(\frac{s(s-1)}{2} \right)^{1_{\chi=1}} (q/\pi)^{\frac{s+a}{2}} \Gamma \left( \frac{s+a}{2} \right) L(s,\chi)$
Here is the definition of ...
- 147
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3
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Integral of the entrywise square of the exponential of a matrix
Note: I posted my question on math.stackexchange but got no answer. That is why I am asking it here.
Let $A$ be a $n\times n$ square matrix such that the real part of all eigenvalues are negative. ...
- 552
0
votes
1
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133
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sub-space restricted minimum eigenvalue of Hadamard product of two PSD matrices
Let $\mathbf{A},\mathbf{B}\in\mathbb{R}^{n\times n}$ be two positive semidefinite matrices. Also let $\mathbf{A}\circ \mathbf{B}$ denote the Hadamard product of $\mathbf{A}$ and $\mathbf{B}$. A ...
- 859
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0
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Matrix equation and Hadamard product
I have a matrix equation involving square real matrices of the form:
$$X(X^{T} \odot A) + (X \odot A)X^{T} = B$$
where $\odot$ denotes the Hadamard product. How can I determine a solution for X?
Any ...
- 21
3
votes
2
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2k
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Matrix equation with Hadamard product and its own inverse involved
I know there is an almost exactly same question here but I have further specifications. So my problem is as follows:
$$
\Omega^{-1}=\dfrac{1}{n}\left(\Omega\odot \mathbf{W}+\mathbf{X}'\mathbf{X}+\...
- 133
2
votes
1
answer
370
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eigenvalues of a generalization of Hadamard product matrix
I have a Laplacian matrix ($L$), which is positive semi-definit. Then I have this matrix
$$\Delta=\begin{bmatrix} \delta_{11} & \ldots & \delta_{1n} \\
\vdots & \ddots & \vdots \\
\...
- 29
3
votes
1
answer
112
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Billera Tree Space
I am studying the tree space of Billera and I do not really understand why it is an Hadamard Space. I have already read L. Billera, S. Holmes, K. Vogtmann, Geometry of the space of phylogenetic trees, ...
1
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1
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Hadamard Product and Eigendecomposition
I just found this related question in here Q1.
Given a positive definite matrix $\mathbf{A}$, consider its eigendecomposition $(\mathbf{A}\mathbf{V} = \mathbf{V}\mathbf{D})$. Consider an arbitrary ...
- 322
1
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0
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172
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Prime Hadamard Matrices
Assume that $n$ is a sufficiently large number. Is there a Hadamaed matrix $H_{4n \times 4n}=(h_{ij})$ with the last row and the last cloumn $J$ (thet is, for every $k$, $h_{k,4n}=1$ and $h_{4n, k}=1$)...
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1
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A Hadamard product of the zeros of the Riemann integral. Does it put any constraints on where the $\rho$'s can reside in the critical strip?
I have deleted a previous, now obsolete question on the same topic.
Take the well-known Riemann integral:
$$\displaystyle \pi^{-\frac{s}{2}}\,\Gamma\left(\frac{s}{2}\right)\, \zeta(s) =\int_1^{\...
- 4,109
3
votes
1
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984
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How to solve a matrix equation with both inverses and a hadamard product?
I have a matrix equation of the form:
$$
A^{-1} = B + A \circ C
$$
where $\circ$ denotes the Hadamard product (i.e., $(A\circ C)_{ij} = A_{ij}B_{ij}$). How can I determine if a solution for $A$ ...
- 375
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1
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575
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Inequalities for Hadamard products of complex symmetric matrices
Consider a complex symmetric matrix $$ C= C_R + i C_I $$ with $C_R,C_I \in \text{Mat}_{n\times n}(\mathbb R)$ symmetric, and assume that the eigenvalues of $C_R$ are all strictly positive. Then, $C$ ...
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2
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416
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Hadamard product and inertia
One of Schur's famous results says that if $A,B$ are positive semidefinite matrices, then the Hadamard (i.e. entrywise) product $A \circ B$ is also positive semidefinite. It's also true if "semi" is ...
- 6,772
4
votes
2
answers
1k
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Generalizations of Oppenheim's inequality
The well-known Oppenheim inequality says that for two positive definite matrices $A,B$ it holds that $\det(A \circ B) \geq (\prod{a_{ii}})\det(B)$.
There has been a lot of beautiful work done ...
- 6,772