\(\pm \) sign pattern matrices that allow orthogonality. (English) Zbl 1164.15327

Summary: A sign pattern \(A\) is a \(\pm \)  sign pattern if \(A\)  has no zero entries. \(A\)  allows orthogonality if there exists a real orthogonal matrix  \(B\) whose sign pattern equals  \(A\). Some sufficient conditions are given for a sign pattern matrix to allow orthogonality, and a complete characterization is given for \(\pm \) sign patterns with \(n-1 \leq N_-(A) \leq n+1\) to allow orthogonality.


15B36 Matrices of integers
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