We classify frame elements in terms of how central they are to a particular frame, distinguishing three levels: core, peripheral, and extra-thematic. A fourth possible value for this attribute, called core-unexpressed is also discussed below. A core frame element is one that instantiates a conceptually necessary component of a frame, while making the frame unique and different from other frames. For example, in the Revenge frame, Avenger, Punishment, Offender, Injury, and Injured party are all core frame elements, because an avenging event necessarily includes these participants. One cannot imagine an act of revenge that is not preceded by a (perceived) offense or one that is not directed against anybody. In determining which frame elements are considered core, we also consider some formal properties that provide evidence for core status. These properties are typically co-present, although they need not be. – When an element always has to be overtly specified, it is core. For instance, the verb resemble in the Similarity frame always requires a post-verbal complement NP denoting an entity that is similar to the entity denoted by the subject. – A frame element which, when omitted, receives a definite interpretation, is also core. For instance, when the verb arrive is used only with a Theme-subject, as in John arrived, a particular Goal location that the Theme reaches still has to be understood in the context. Goal, therefore, must be a core frame element. – A frame element whose semantics cannot be predicted from its form, in particular from any marking prepositions, ought to be core since its interpretation completely depends on the target. From this, we can derive two corollaries, given below. -- A frame element that has no formal marking should be core. Thus, frame elements that can be subject or object in a simple active sentence ought to be core since these slots host frame elements of many different kinds and knowing that something is a subject or object is not particularly informative. For example, the Building frame which contains the verb build has at least two core frame elements since the verb build has both a subject and an object. –- A frame element that has idiosyncratic formal marking should also be core. A good example of this is the prepositional verb depend on. The preposition on does not occur as a marker of the same meaning with predicates in many other frames. In its basic spatial sense of ’in contact with and supported by’, on occurs in many different frames; as a marker of Place or Location frame elements it is totally unremarkable and does not suggest core status for these FEs. Frame elements that do not introduce additional, independent or distinct events from the main reported event are characterized as peripheral. Peripheral FEs mark such notions as Time, Place, Manner, Means, Degree, and the like. They do not uniquely characterize a frame, and can be instantiated in any semantically appropriate frame. In respect to the Revenge frame, any report of an event of revenge may also include explicit information about the parameters of time, place, manner, etc. of the revenge, an example of which is given below. (8) The bereaved family retaliated [immediately Time]. Extra-thematic frame elements situate an event against a backdrop of another state of affairs, either of an actual event or state of the same type, as illustrated with Iteration, or by evoking a larger frame within which the reported state of affairs is embedded, as shown for Containing event. (9) Thou shalt not exact revenge [twice Iteration] for the same offense. (10) The Aussies took revenge [in a penalty shootout before 2465 fans in Long Beach the next day Containing event]. Note that extra-thematic frame elements are understood not to conceptually belong to the frames they appear in. We take them to properly be frame elements of other abstract frames that take them as well as the targets that they modify as arguments. Thus, in example (11), we take twice and the verb phrase eat to be arguments of a more abstract Iteration frame. Similarly, in example (12), cooked dinner and me are frame elements of a Benefaction frame. Note that, as shown by (12), the native frame of the extra-thematic frame element need not be evoked by lexical material, it may simply be evoked constructionally. (11) Learn how to spend a few extra minutes planning complementary menus where you cook once and eat [twice]. (12) Lennert, another sweetie in my life, cooked [me] dinner, mmm mmm good. The view of extra-thematic frame elements presented here entails that these frame elements are necessarily the same across all the ‘host’ frames in which they appear. That is, unlike core and peripheral frame elements, extra-thematic frame elements do not have a frame-specific understanding. By comparison, although many core frame elements named Agent share properties with each other due to Inheritance and Using relations, they do not necessarily have identical properties. The value “Core-Unexpressed” is a special notational shorthand. It is assigned to FEs that behave like core frame elements in the frame where they are marked as Core-unexpressed but which, counter to expectation, may not be used for annotation in descendants of that frame. Frame elements marked as core-unexpressed will thus not necessarily be listed among the FEs in descendant frames. We do not consider core-unexpressed frame elements to be violations of our definition of full inheritance. Our reasoning can be illustrated with the example of the core-unexpressed Act frame element in the Intentionally act frame, which is exemplified in (13). (13) I’ll do [the vacuuming Act]. In the many child frames of Intentionally act such as Choosing, Perception active, etc., the idea of an Act is as relevant as in the Intentionally act parent frame. However, in the child frames the frame element is absorbed by the lexical units in the frame and cannot be separately expressed. Marking the frame element Act as core-unexpressed in the Intentionally act parent frame allows us to keep the frames that are lower in the hierarchy from including an inherited FE which for any lexical unit in the frame could at most be annotated on the target itself, but never be expressed separately. The sentence *I chose decision the blue one is simply ungrammatical. Coreness marking makes the most sense for event and state frames, and in these frames we use all three statuses. Coreness marking is done at the level of the frame and is intended to be consistent for all lexical units in a frame. In frames whose LUs are artifacts or natural kinds, we only use a two-way distinction (core and peripheral), noting that the values do not have exactly the same meaning as with events. In such cases, typically there is just one core frame element which is marked on the target word. For instance, in the Clothing frame the FE Clothing is core, and all other FEs are peripheral. xsd:string