[...] an MS CONDITION is a finite statement of a property shared by some, but not all, matrices in U. Thus "has two segments (columns)", "begins with a [+Consonantal] segment", "has no two consecutive [-Vocalic] segments", etc. are all examples of MS conditions. It is easy to ee that each MS condition divides the set U into two parts, one part consisting of all matrices which possess the property stated in MS condition, and another part consisting of all other matrices in U [...]. Specifically we will be considering three kinds of MS conditions: "if-then" conditions, "positive" conditions, and "negative" conditions [...].
- Stanley (2004), Pag. 76-77

[...] MS rules can be replaced by a new device, MS CONDITIONS. [...] MS rules and MS conditions are very similar. In particular, we can talk about segment structure CONDITIONS and sequence structure CONDITIONS in the same way that we talked about the corresponding kinds of RULES.
- Stanley (2004), Pag. 75-76