GM-RKB: Classification Function

AKA: Classifier, Categorical Function, Category-Valued Function, Class-Output Function, Categorical-Output Function, Classification Structure, Classification Scheme.
Context:
- It can be:
  - a Binary Classification Function.
  - a Multi-Valued Classification Function.
- It can be:
  - a Probabilistic Classification Function, such as on that predicts the Outcome of a Random Experiment with a Categorical Sample Space.
  - a Deterministic Classification Function, such as a Deductive Logic Formula.
- It can be:
  - a Predictive Classifier, with a Probability Value.
  - a Heuristic Classifier.
  - a Categorical Random Variable.
- It can be:
  - a Generative Classification Function.
  - a Discriminative Classification Function.
- It can a:
  - Deduced Classification Function.
  - Induced Classification Function, (that was induced by a Classification Function Learning Task).
  - Heuristic Classification Function.
Example(s):
- f(1.1,2.3,3.9) => +1.
- f(1.1,Yellow,3.9) => Red.
- a Text Classification Function.
Counter-Example(s):
- f(1.5) => 5.1, a Real-Valued Function.
- f(1.1,Yellow,3.9) => 0.37, , a Real-Valued Function.
- f(1.5) => 1, an Integer-Valued Function.
- f(1.5) => Large, an Ordinal-Valued Function.
- f(1.5) => (3.1,2.3), a Vector-Valued Function.
See: Predictive Classifier, Ordinal Function, Numeric Function, Concept Scheme, Subject Heading List.

References

(Dextre Clarke & al, 2008) => Stella Dextre Clarke, Alan Gilchrist, Ron Davies and Leonard Will. (2008). "Glossary of Terms Relating to Thesauri and Other Forms of Structured Vocabulary for Information Retrieval." Willpower Information
- classification scheme
  - schedule of concepts, arranged by classification

http://gondolin.rutgers.edu/MIC/text/how/catalog_glossary.htm
- A scheme, usually consisting of numbers or alphanumericor other notation that categorizes or subdivides a subject area or collection of materials. Most classification schemes were originally intended to organize physical items on the shelf. The result was a unique shelving location (call number) for each item that facilitated browsing of material by subject or author.

(Woodley, 2005b) => Mary S. Woodley, Gail Clement, and Pete Winn. (2005). "DCMI Glossary." Dublin Core Metadata Initiative.
- classification
  - A logical scheme for arrangement of knowledge, usually by subject. Classification schema are alpha and/or numeric; for example, Library of Congress Classification, Dewey Classification, Universal Decimal Classification.

(Kohavi & Provost, 1998) => Ron Kohavi, and Foster Provost. (1998). "Glossary of Terms." In: Machine Leanring 30(2-3).
- Classifier: A mapping from unlabeled instances to (discrete) classes. Classifiers have a form (e.g., decision tree) plus an interpretation procedure (including how to handle unknowns, etc.). Some classifiers also provide probability estimates (scores), which can be thresholded to yield a discrete class decision thereby taking into account a utility function.

(Kohavi, 1995) => Ron Kohavi. (1995). "A Study of Cross-Validation and Bootstrap for Accuracy Estimation and Model Selection." In: Proceedings of the Fourteenth International Joint Conference on Artificial Intelligence (IJCAI 1995).
- A classifier is a function that maps an unlabelled instance to a label using internal data structures. An inducer or an induction algorithm builds a classifier from a given dataset. CART and C 4 5 (Brennan, Friedman Olshen &. Stone 1984, Quinlan 1993) are decision tree inducers that build decision tree classifiers. In this paper we are not interested in the specific method for inducing classifiers, but assume access to a dataset and an inducer of interest.