-Nun is generally known as a Topic marker in Korean. However, when it is combined with an accent, it is thought to have a different function, which is alleged to indicate 'contrast' (Kuno 1972). Although the fact that -nun marked item generates some kind of 'contrastive meaning' is uncontroversial, what 'contrast(ive)' means is still unclear. In t his paper, I propose that accented -nun generates two types of implicit propositions in addition to its at-issue meaning. A simple sentence has been repeatedly tested in various models in order to see what type of proposition each proposition corresponds to and it has been concluded that one is presupposition and the other is implicature. This tedious-looking test forms the main part of the first-half of this paper. The presupposition is the essential factor for the -nun marked item to obtain the 'contrastive' meaning. Based on the generation of this presupposition, I argue that -nun works as a contrast operator in a sentence. To illustrate -nun's function as a contrast operator forms the latter part of this paper.

This study introduces set-denoting time expressions in Korean, which can be divided into simple and complex types. It was found that while the simple type expressions are easily represented within ISO-TimeML, a time-expression markup language, some complex type set-denoting expressions are not. Therefore, this study analyzes the reason for these difficulties in representing complex type expressions, as well as suggests the introduction of @measure and @interpretation attributes in the TIMEX3 tag. The @measure attribute represents the time interval, and the @interpretation attribute is used to distinguish distributive readings from cumulative readings. Additionally this paper suggests that a mapping between these and other attributes are required in TLINK.