Term: types, format
In NARS a term refers to a concept within the system, as a part of a sentence that expresses the relation between some concepts.
Consider a sentence (discussed below) "Ravens are black", in Narsese it can be represented as
<raven --> [black]>.%1.0;0.9%
Now both "raven" and "[black]" are terms that in this particular case along with inheritence copula create a statement. The statement plus the punctiation and truth-value form a judgment, which is a type of sentence. In more complex Narsese sentences, terms may be statements themselves. For example, consider sentence "John knows that whale is a kind of mammal" that is
<(*, {John}, {<whale --> mammal>}) --> knows>. %1.0;0.9%
Here term "<whale --> mammal>" is a statement itself that consists of simpler terms "whale" and "mammal" which all are part of a sentence.
In the above example, a term can be one of three types: atomic, compound, and statement (which is a special type of compound term). All three types of terms can have relations with each other.
An atomic term is just a word as in the first example, it is a unique identifier with no internal structure.
A compound term is more complex. It is formed by a connector from one or more terms, called its components. The order of components usually matters. In the second example there is a compound term (*, {John},{<whale --> mammal>}) here it consists of two components "{John}" and "{<whale --> mammal>}" connected by the product connector "*". All connectors are listed in the grammar of Narsese.
A statement is a special type of compound term that can be part of a bigger compound term. Such a term only has a binary truth-value, except that it is the outermost statement that is not a component of an even larger compound. As in the second example, <whale --> mammal> is a statement that is a component of a larger compound term, and it only states that "whale is mammal" with an implicit truth-value "true", which is different from the numerical truth-value attached to the entire sentence.
Syntactic Complexity: the syntactic complexity of a term is defined recursively. If it is atomic its syntactic complexity is 1. If it is a compound, then its syntactic complexity is one plus the sum of the syntactic complexities of its components. As the name suggests, this measurement says nothing about the semantic complexity of the term and the concept it refers to.