Rigorous Reasoning

Concept · Foundations

Function

A function f: A → B is a relation from A to B such that for every a ∈ A there is exactly one b ∈ B with (a, b) ∈ f; we write f(a) = b for this unique value.

Why it matters

Functions capture the idea of well-defined assignment and are the most widely used relational structure in mathematics and logic.

Where this shows up

Units and lessons using this concept

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Related

Other concepts in Foundations

A, E, I, O PropositionsAccessibility RelationArgumentAtomic StatementAuthorial IntentBase RateBayes FactorBurden of Proof in InterpretationCalibrationCardinalityCartesian ProductCategorical Proposition