Rule Extraction
The category representations discussed above are all extensional in nature; that is, a category or complex class is simply the sum of all its members. To represent a category is, then, just to be able to list or identify all the objects belonging to that category. However, extensional category representations have very limited practical use, because they provide no insight for deciding whether novel (never-before-seen) objects are members of the category.
What is generally desired is an intentional description of the category, a representation of the category based on a set of rules that describe the scope of the category. The choice of such rules is not unique, and therein lies the issue of inductive bias. See Version space and Model selection for more about this issue.
There is a few rule-extraction methods. We will start from a rule-extraction procedure based on Ziarko & Shan (1995).
Read more about this topic: Rough Set
Famous quotes containing the words rule and/or extraction:
“Resolved to ruin or to rule the state.”
—John Dryden (1631–1700)
“Logic is the last scientific ingredient of Philosophy; its extraction leaves behind only a confusion of non-scientific, pseudo problems.”
—Rudolf Carnap (1891–1970)