Most existing causal discovery methods rely on the assumption of no latent confounders, limiting their applicability in solving real-life problems. In this paper, we introduce a novel, versatile framework for causal discovery that accommodates the presence of causally-related hidden variables almost everywhere in the causal network (for instance, they can be effects of observed variables), based on rank information of covariance matrix over observed variables. We start by investigating the efficacy of rank in comparison to conditional independence and, theoretically, establish necessary and sufficient conditions for the identifiability of certain latent structural patterns. Furthermore, we develop a Rank-based Latent Causal Discovery algorithm, RLCD, that can efficiently locate hidden variables, determine their cardinalities, and discover the entire causal structure over both measured and hidden ones. We also show that, under certain graphical conditions, RLCD correctly identifies the Markov Equivalence Class of the whole latent causal graph asymptotically. Experimental results on both synthetic and real-world personality data sets demonstrate the efficacy of the proposed approach in finite-sample cases.

在这篇论文中，我们介绍了一种新颖且多用途的因果发现框架，它几乎可以适用于因果网络中几乎任何地方存在的具有因果关系的隐藏变量（例如，它们可以是观测变量的效应）。通过研究秩与条件独立性的有效性，我们在理论上建立了某些潜在结构模式可辨识性的必要和充分条件。此外，我们开发了一种基于秩的潜在因果发现算法（RLCD），可以高效地定位隐藏变量，并确定它们的基数，发现包括测量和隐藏变量在内的整个因果结构。我们还证明，在某些图形条件下，RLCD能够渐近地正确识别整个潜在因果图的马尔可夫等价类。在合成和真实的个性数据集上的实验结果证明了该方法在有限样本情况下的有效性。

一个通用的因果推断框架，允许有因果关系的隐藏变量