If ... then ...
The construction If ... then ... is used for making an implication (semantic rule). The construction can be used for two purposes: SWRL rules and axioms about properties/roles. In SWRL rules about concept and roles variables appear with a/the prefix. There is a special class of semantic rules - axioms about roles in which X/Y variables are used. Both antecedent and consequent clauses in the implication can be complex sentences.
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 number in parenthesis marks more variables of the same type.|
Those examples show how to write semantic rules with the construction If ... then ....