  In this paper, we address the problem of identifying linear structural
equation models. We first extend the edge set half-trek criterion to cover a
broader class of models. We then show that any semi-Markovian linear model can
be recursively decomposed into simpler sub-models, resulting in improved
identification power. Finally, we show that, unlike the existing methods
developed for linear models, the resulting method subsumes the identification
algorithm of non-parametric models.
