Mathematical Foundations·Rules·Lesson 4 of 5

Functions and Cardinality

Defines a function as a well-defined relation, introduces injective, surjective, and bijective functions, develops cardinality for finite and infinite sets, states the pigeonhole principle, and presents Cantor's diagonal argument in intuitive form.

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In this lesson · 7 sections · 2 worked examples · 4 practice activities

A function is a relation with a uniqueness condition
Injections: no collisions allowed
Surjections and bijections: filling the codomain and perfect pairing
Composition of functions and inverses
…and 3 more

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