Concept · Foundations

Cardinality

A measure of the size of a set; two sets have the same cardinality when there exists a bijection between them, and a set is countable when it has the same cardinality as the natural numbers.

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Why it matters

Cardinality extends the everyday notion of 'how many' to infinite sets and is the setting in which Cantor's diagonal argument distinguishes the countable from the uncountable.

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Units and lessons using this concept

Following the links will take you to the page where this term is introduced in context.

Units (1)

Set Theory and Relations: The Structure Underneath LogicStudents learn the language of sets, relations, and functions that underlies most of modern formal logic. They master set operations, rel…

Lessons (1)

Functions and CardinalitySet Theory and Relations: The Structure Underneath Logic

Other concepts in Foundations

A, E, I, O Propositions Accessibility Relation Argument Atomic Statement Base Rate Bayes Factor Calibration Cartesian Product Categorical Proposition Categorical Syllogism Circularity Compound Statement