A / an

English indefinite article a/an indicates some unspecified individual of a given concept. Individuals start with capital letter and are never preceeded by a/an. Concepts start with small letter and can be preceeded by a/an. Variables appear in semantic rules. When a variable occurs for the first time it is preceeded by a/an and later by the.

Different use cases of variables in semantic rules are summed up in the table below.

Variable pattern Use case
a/the class-name  denotes variables assigned to a class/concept
a/the thing  represents an instance of the top concept "owl:Thing" and thus any variable in the SR-CE sentence.
a/the class-name(n)/thing(n)  different numbers in parenthesis mark more variables of the same type.


Example: Here concepts are preceeded by 'a', referring to an unspecified earlier individual of a given concept.
Sophie is a giraffe.
Leo is a lion.
Example: Word 'every' is used to refer to all individuals of given concept, word 'a' refers to some unspecified individual of given concept.
Every giraffe is an animal.
Every lion is an animal.
Example: In the semantic rule below, there is one variable 'person'.
If a person has-age-in-years greater-or-equal-to 18 then the person is an adult-person.
Example: In the semantic rule below, there is a variable which could be anything.
If a thing is a person then the thing has-species-name equal-to 'homo-sapiens'.
Example: In the semantic rule below, there are two variables 'person'.
If a person(1) has-parent a person(2) and the person(2) is a female-person then the person(1) has-mother the person(2).