Fig. 2From: Star-causality and factor analysis: old stories and new perspectivesStar-causality and factor analysis: new perspectives. a Lumping factors into a vector \(\mathbf{W}=[W_1,\ldots , W_4]\). b Triplet star-decomposable in blocks. c Block decomposition of covariance matrix [see pp 51–53 in Gigi (1977)].Back to article page