AI-generated prose accompanying the Agda code. These notes are supplementary to the book and are not part of the authors' manuscript.
Chapter 1: The language of synthetic category theory
Coherences
- Specializing coherence laws AI-generated
Projection computations and endpoint comparisons when substituting into the universal coherence laws.
- Whiskering and horizontal composition AI-generated
The five derived whiskering laws and the middle interchange in horizontal composition.
Equivalences of categories
- Changing endpoints in identification animae AI-generated
Endpoint transport, equivalences of identification animae, and lifts with specified images.
- Pairing and precomposition AI-generated
Projection tests for pairing, naturality, and compatibility with successive and identity substitutions.
Mapping animae
- Decoding mapping animae and restriction AI-generated
The decoding equivalence on identification animae and its full compatibility square with restriction.
Initial categories and coproducts
- Identifications on coproducts AI-generated
From the mapping-anima universal property to restriction of identifications, with prescribed images on both summands.
Pullbacks of categories
- Restricting and pasting cone diagrams AI-generated
Restriction comparisons, pasted matchings, and the factorization equation behind pullback pasting.
- Fiber squares and diagonal squares AI-generated
Recovering fiber cones from diagonal coordinates and deriving the specified diagonal representability square.
Functor categories
- Uncurrying and pullback squares AI-generated
The cone comparisons and matching compatibility behind preservation of pullbacks by functor categories.
Pushout squares
- Mapping out of pasted squares AI-generated
The full matching comparison needed to turn pushout pasting into pullback pasting on mapping animae.
Chapter 2: The internal structure of categories
Morphisms and diagrams
- Arrows with specified endpoints AI-generated
Endpoint frames and the full pullback computation law for families of arrows with prescribed source and target.
The Segal axiom
- Substitution in morphism expressions AI-generated
Endpoint-preserving restriction, successive substitutions, and changes of parameters in chosen composite presentations.
The Rezk axiom
- Reordering inverse conditions AI-generated
Changing the order of pullback constraints while retaining the projection to a family of invertible arrows.
Groupoids
- Constant diagrams and the exponential law AI-generated
Naturality and exponential compatibility of constant diagrams, with the coproduct comparison used in recognizing animae.
Recognizing animae
- Constant diagrams and the exponential law AI-generated
Naturality and exponential compatibility of constant diagrams, with the coproduct comparison used in recognizing animae.
Exercises
- Hom expressions and restriction AI-generated
Normalization of endpoint cones and computation of the hom-category composition functors under restriction.
Chapter 3: Constructions of categories
Subcategories
- Lifting a family from three restrictions AI-generated
Gluing specified family lifts and recovering the arrows of a generated subcategory.
Full subcategories
- From object families to arrow families AI-generated
Endpoint computations turning a coherent object-family factorization into a family of functors through a full subcategory.
Localizations
- Lifting prescribed identifications through localization AI-generated
Lifting identifications with their prescribed restrictions and reflecting the matching equations of cocones.
Geometric realizations
- Lifting prescribed identifications through localization AI-generated
Lifting identifications with their prescribed restrictions and reflecting the matching equations of cocones.
- Inverting the walking morphism AI-generated
Evaluating the inversion data at the identity functor and identifying the localization of the interval.
Exponentiable functors
- Triangles over a base AI-generated
Naming, decoding and comparing functors while retaining their specified triangle over the base.
- Base change of triangles AI-generated
Base-change comparisons, including the full pullback-cone and base-triangle computations for composition.
- Relative currying and evaluation AI-generated
Computing relative uncurrying on named triangles and deriving the finite laws for the induced dependent-product action.
Joins
- The attaching maps of a join AI-generated
Normalizing the join span and retaining the full cocone comparison for its pushout-defined action.
Slice categories
- Endpoint coordinates for slice categories AI-generated
Exponential restriction, constant families and cylinder coordinates in the specified absolute slice pullback.
Exercises
- Lifting prescribed identifications through localization AI-generated
Lifting identifications with their prescribed restrictions and reflecting the matching equations of cocones.
- Relative currying and evaluation AI-generated
Computing relative uncurrying on named triangles and deriving the finite laws for the induced dependent-product action.