提问：数学中，atomless function是什么意思？

原文如下： Firm X does not observe 0 and has a prior, atomless,distribution of θ ∈ R+, with a strictly increasing cumulative distribution function,which is known to firm Y.


文献来源：Yosha, O., 1995.Information disclosure costs and the choice of financing source. Journal of Financial Intermediation 4:3–20.（第7页、第一段、第四行）