The four main properties of a sign have complex values whose structure is summarised in the following nested attribute value template (with illustrative values inserted), which will be referred to as the ILEX template:
The attributes have the following interpretations (abbreviations in parentheses):
- LEMMA: Name of the lexical entry; the lowest type in the inheritance hierarchy; it can be compared with types in HPSG (except that the ILEX approach uses default inheritance lattices, while HPSG uses type subsumption lattices).
- STRUCTURE (STRUC): The syntagmatic properties of the sign.
- CATEGORY (CAT): The relation of a head sign to its parent and siblings (cf. HPSG `HEAD' and `SUBCAT' attributes).
- PARTS: The constituents of a sign (cf. HPSG `DTRS').
- HEAD: The head constituent (cf. Zwicky [Zwicky 1993]).
- MODIFIER (MODI): The non-head constituents of a sign (cf. HPSG `COMP'); for noun compounds, generally a single item.
- INTERPRETATION (INT): The basic semiotic properties of a sign.
- MEANING (MEAN): The semantic interpretation attribute.
- EVENT: Taken from Generative Lexicon Theory (cf. Pustejovsky [Pustejovsky 1996]).
- QUALIA: Taken from Generative Lexicon Theory.
- RELATION (RELN): Taken from HPSG-flavoured semantic role structure.
- TECHNICAL (TECH): Indicates a technical meaning from a special sublanguage.
- INDEX: Taken from HPSG-flavoured situation semantics.
- SURFACE (SURF): The phonetic/orthographic interpretation attribute.
- PHON: Phonetic interpretation (with prosodic association and concatenation, when represented in full detail).
- ORTH: Orthographic interpretation.
Values which are shared by a class of signs (i.e. values defining paradigmatic
similarity relations) may be generalised by applying the operator `
'
to the AVMs of the signs.
In this case, the values are inherited from the `archi-sign'
representing this class, and need not be represented explicitly for each
member of the class.
Inheritance therefore expresses implication,
the paradigmatic relation which constitutes taxonomies.
For example, serenity inherits
certain phonological properties from the archi-sign representing the class
of English words affected by tri-syllabic shortening;
bake inherits the
details of its inflections from the archi-sign representing the class of
all weak verbs; chair inherits certain general semantic
properties from the archi-sign representing all items of furniture;
surfboard inherits compositional properties from the archi-sign
representing the class containing skateboard and blackboard,
and in particular it inherits `head features' such as CAT
from its HEAD PART board.
The inheritance of properties from (or by) a PART is commonly referred to as feature percolation, and defines the notion of compositionality in attribute-value terms.
The four main kinds of inheritance, which are closely related to mechanisms in the DATR lexical knowledge representation language, are listed in Table 1.
Orthogonal multiple inheritance simply means that the values of several different specified attributes may be inherited from different archi-signs or types, rather than from a single archi-sign for the CAT attribute. In general, any attribute which is not explicitly specified inherits its value from the archi-sign; the notation given here permits explicit expression of this relation.
