Criteria for Confounders in Survival Function

In this paper, we discuss the criteria for detecting confounders in the survival function under the assumption that the response and covariates are both continuous. By the partition-based method, we propose the necessary and suffcient conditions for a uniformly irrelevant factor when a covariate is one-dimensional. Then the suffcient conditions for a conditional uniformly irrelevant factor vector are also obtained when a covariate is multidimensional. We propose the criteria for detecting a single confounder and multiple confounders in survival function.