This kind of
rule is found in
expert systems ,
knowledge bases, and
logic texts/
tests. And (some say) in
people's heads.
"Rule" in the context of expert systems and knowledge bases is usually used to refer to statements that use logical implication -- if A, then B. This can be written
A -> B
Or, for a more concrete (albeit fanciful) example,
X is a polar bear -> X works for Coca Cola
If you have a system with an inference engine that knows this rule, and it learns that Ferdinand is a polar bear, it can use the rule to infer that our pal Ferdinand is getting his blubber money from the Coke guys.