%0 Journal Article
%T Rational Orthogonal versus Real Orthogonal
%A Dragomir Z. Djokovic
%A Simone Severini
%A Ferenc Szollosi
%J Mathematics
%D 2009
%I arXiv
%X The main question we raise here is the following one: given a real orthogonal n by n matrix X, is it true that there exists a rational orthogonal matrix Y having the same zero-pattern? We conjecture that this is the case and prove it for n<=5. We also consider the related problem for symmetric orthogonal matrices.
%U http://arxiv.org/abs/0903.2853v1