Functions, domain and codomain
A function assigns exactly one output to each input in its domain.
Key knowledge
A function f:A→B assigns exactly one element of B to each element of A. A is the domain, B the codomain, and the range consists of outputs actually attained.
Values and equations
f : A → B
- f
- Function
- A
- Domain
- B
- Codomain containing every output
Conditions and scope
- This record uses the total-function convention; a partial function may be undefined on some inputs.
- Declare the domain and codomain; different inputs may share an output.
- An undefined expression at an input does not give a function value there.
Sources · 4
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Unique output, domain, codomain and range.
2026-10-10 · Compared elementary total-function notation with MIT's explicit distinction between partial and total functions.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Agreement within this scope
Total functions give one output per input, distinct from partial functions.
The source explicitly preserves the total-function convention and domain/codomain.
University of Cambridge, Computer Laboratory
- Discrete Mathematics II · Set theory for computer science United KingdomEnglish
§2.2 Relations and functions, pp.34–35
- Discrete Mathematics II · Set theory for computer science
Entry details
Permanent link to this entry ↗- Record identity
- math-functions
- Revision
- core.1
- Structured reference record
- Essential core · first collection