Verb

A verb is a LRU that denotes an action (bring, read, walk, run, murder), an occurrence (decompose, shine), or a state of being (exist, stand).

Natural Language

In the UNL^arium framework, verbs are classified as follows:

• A lexical verb (VER) is the head of a verb phrase, i.e., a word that denotes an action, an occurrence or a state of being;
• A copula (COP) (such as "be", "become", "seem"), also called "linking verb", is used to link the subject of a sentence with a predicate (a subject complement or an adverbial).
• An auxiliary verb is a verb functioning to give further semantic or syntactic information about the main verb of the phrase. Auxliary verbs are classified as inflections (I). They can be:
  • A simple auxiliary verb (AUX) (such as "will" in "I will go", "do" in "I don't go", or "have" in "I had gone") if used only to convey information about tense and aspect;
  • A modal verb (MOD) (such as "can", "must", "have to") if used to indicate modality.

Several verbs may be either lexical or auxiliary depending on the context

• I have a book (have = lexical verb)
• I have read the book (have = auxiliary verb)
• He appears to be tired (appear = modal verb)
• He appeared in the party (appear = lexical verb)

UNL

In UNL, lexical verbs are represented as UWs, whereas auxiliary verbs are represented as attributes. The copula verb is represented by relations (see be for further information).

• I have a book = aoj(have, I), obj(have, book)
• I have read a book = aoj(read.@perfect, I), obj(read.@perfect, book)
• He appears to be tired = aoj(tired.@belief, he)
• He appeared in the party = agt(appear.@past, he), plc(appear.@past, party)