Statement
A statement is a clause containing an affirmation or negation that can be truthful or not.
Examples of statements include assigning properties and relations to entities or stating a given event has or has not happened. For instance, the statement:
Earth is black
Declares about the entity "earth" that it "is black".
If we were to think of this statement as the basis for a property, then "earth" would be the entity the property belongs to, "color" would be the property itself, and "black" its value.
A statement can be recursively separated into a root (the verb) and its arguments, one of which is a subject and the other an object:
ROOT
is [V]
|
.---^---.
| |
[S] Earth black [O]
|
The --'
The Earth is black
This approach, known as dependency grammar, moves away from the binary dichotomy between subject and predicate and instead focuses on finding a locus of structure or meaning called the "head" or "root" of the clause.
In this example, however, the verb "is" carries no meaning regarding the quality of this being. It merely acts as a link between the subject and object. This is called a copula. It has an important role, since otherwise "Earth black" would be less clear structurally. Despite this, the core meaning is not completely lost, and it would be if we instead had removed any of the other words.
Copulas shift the semantics onto the predicate, making us derive the property "color" from the question of "what is the object?". This shows how in dependency grammars we have more than one dependency kind. While syntactically (regarding the phrase structure) Earth and black depend on is, semantically (regarding its meaning) Earth and is depend on black.
For this reason, some dependent grammars avoid copular roots. In this case, the adjective black would then be the root. From this perspective, the tree looks like this instead:
ROOT
black [O]
|
.--------'
| |
[S] Earth is [V]
|
The --'
The Earth is black
This allows us to create a clear mapping from statements to properties:
Statement Property
--------- --------
Subject --> Entity --> Earth
Root --> Property --> Color
Object --> Value --> Black
Let's take a more complex example:
ROOT
irrelevant
|
.-------------------------------------------|
| |
Distinguishing is ----'
|
'-----------------------------.
| |
statements propositions
|
from ------'
Distinguishing statements from propositions is irrelevant.
We could map this to a property in several ways:
Statement Property
--------- --------
Subject --> Entity --> Distinction: statement, proposition
Root --> Property --> Relevance
Object --> Value --> Irrelevant
Subject --> Entity --> Distinction: statement, proposition
Root --> Property --> Relevant
Object --> Value --> False