Fundamental concepts

The 3 fundamental concepts at the heart of category theory:

  • Category

  • Functor

  • Natural Transformation

A category is the main object of concern, it consists of a network of arrow-connected objects.

A functor is a mapping between categories that preserves strutcure. A functor maps both objects and arrows in a category; it maps objects to objects, and arrows to arrows.

A natural transformation is a another mapping, this time between functors.

Acquired terminology:

  • category theory

  • category

  • object

  • arrow, morphism

  • composition of arrows

  • associativity of arrow composition

  • identity arrow, identity wrt arrow composition

  • functor

  • natural transformation

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