Mohamed Zouagui

collaborators

3 papers

math.CO2024

Quasi-orthogonal extension of symmetric matrices

Abderrahim Boussaïri, Brahim Chergui, Zaineb Sarir +1

An $n \times n$ real matrix $Q$ is quasi-orthogonal if $Q^{⊤} Q = q I_{n}$ for some positive real number $q$ . If $M$ is a principal sub-matrix of a quasi-orthogonal matrix $Q$ , we sa…

math.CO2024

Quasi-orthogonal extension of skew-symmetric matrices

Abderrahim Boussaïri, Brahim Chergui, Zaineb Sarir +1

A real matrix $Q$ is quasi-orthogonal if $Q^{⊤} Q = q I$ , for some positive real number $q$ . We prove that any $n \times n$ skew-symmetric matrix $S$ is a principal sub-matrix of a s…

math.CO2021

$k$ -spectrally monomorphic tournaments

Abderrahim Boussaïri, Imane Souktani, Imane Talbaoui +1

A tournament is $k$ -spectrally monomorphic if all the $k \times k$ principal submatrices of its adjacency matrix have the same characteristic polynomial. Transitive $n$ -tournaments…

Quasi-orthogonal extension of symmetric matrices

Quasi-orthogonal extension of skew-symmetric matrices

k-spectrally monomorphic tournaments

$k$ -spectrally monomorphic tournaments