Quadratic Form of a Skew Symmetric MatrixOctober 26, 2024 While reading some control theory books or papers you may stumble onto expressions like the following:S S is a skew-symmetric matrix (i.e. S=−ST S = -S^T ) so we have XTSX=0 ∀X X^T S X = 0 \space \space \forall X With no demonstrations whatsoever.