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4 votes
1 answer
170 views

About $CW(512,16^2)$

Definitions: A weighing matrix $W = W(n,k)$ with weight $k$ is a square matrix of order $n$ and entries $w_{ij}$ in $\{0, \pm 1\}$ such that $WW^T=kI$, where $I$ is the identity matrix. A circulant ...
5 votes
1 answer
141 views

On the half-skew-centrosymmetric Hadamard matrices

Definition 1: A Hadamard matrix is an $n\times n$ matrix $H$ whose entries are either $1$ or $-1$ and whose rows are mutually orthogonal. Definition 2: A matrix $A$ is half-skew-centrosymmetric if ...
6 votes
1 answer
151 views

How to construct a skew Hadamard matrix of order 756?

Where can I find the construction for a skew Hadamard matrix of order 756? According to multiple papers (e.g. Koukouvinos and Stylianou - On skew-Hadamard matrices and Seberry - On skew Hadamard ...
10 votes
1 answer
319 views

Construction of skew-Hadamard matrix of order 292

I am currently looking into how to construct a skew-Hadamard matrix of order 292. Where can I find such construction? According to multiple papers (e.g. Koukouvinos and Stylianou - On skew-Hadamard ...
3 votes
0 answers
148 views

Linear combinations of special matrices

I am a hobby computer scientist and I have a problem to which I am searching an efficient algorithm. Given an integer n, we want to combine some square input-matrices of size n in a way that is ...
11 votes
4 answers
5k views

Maximum determinant of $\{0,1\}$-valued $n\times n$-matrices

What's the maximum determinant of $\{0,1\}$ matrices in $M(n,\mathbb{R})$? If there's no exact formula what are the nearest upper and lower bounds do you know?
12 votes
3 answers
4k views

Status of Hadamard matrix conjecture

I would like to know if any progress has been made on Hadamard conjecture : Hadamard matrix of order $4k$ exists for every positive integer $k$.