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13 changes: 3 additions & 10 deletions DATABASE.md
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Expand Up @@ -14,13 +14,6 @@ The `structures` table stores data that is common to all types of categorical st

- `structure_types`

Structure-specific data is stored in additional tables, such as:

- `categories`
- `functors`
- `morphisms`
- `symmetric_monoidal_categories`

Properties (whether satisfied or not) are associated with categorical structures via the following table:

- `property_assignments`
Expand All @@ -34,7 +27,7 @@ These tables are abstracted through the `implications_view` view.

Functor implications may also depend on properties of the domain or codomain category. Likewise, morphism implications may depend on properties of the ambient category. Such dependencies are stored in the following table:

- `mapped_assumptions`
- `associated_assumptions`

Additional tables are available. For a complete overview, see the diagram below.

Expand Down Expand Up @@ -110,6 +103,6 @@ to check for redundant assignments of properties to categorical structures.

## Diagram

This is the database schema as of 13.08.2026; changes may occur.
This is the database schema as of 15.08.2026; changes may occur.

<img alt="database diagram" src="https://github.com/user-attachments/assets/72da5e08-3eaf-48f4-9e00-bd0d865a2c92" />
<img alt="database diagram" src="https://github.com/user-attachments/assets/a2cb788e-cac0-44c6-80fc-ae07de2fe83a" />
6 changes: 3 additions & 3 deletions database/data/functor-implications/adjoints.yaml
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Expand Up @@ -9,7 +9,7 @@
- id: saft
assumptions:
- continuous
mapped_assumptions:
associated_assumptions:
domain:
- cogenerating set
- complete
Expand All @@ -34,7 +34,7 @@
- id: representable_right_adjoint
assumptions:
- representable
mapped_assumptions:
associated_assumptions:
domain:
- locally essentially small
- coproducts
Expand All @@ -45,7 +45,7 @@

- id: initial_object_as_left_adjoint
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- initial object
codomain:
Expand Down
30 changes: 15 additions & 15 deletions database/data/functor-implications/limits preservation.yaml
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Expand Up @@ -29,7 +29,7 @@
assumptions:
- preserves terminal objects
- preserves binary products
mapped_assumptions:
associated_assumptions:
domain:
- finite products
conclusions:
Expand All @@ -41,7 +41,7 @@
assumptions:
- preserves equalizers
- preserves products
mapped_assumptions:
associated_assumptions:
domain:
- products
conclusions:
Expand All @@ -53,7 +53,7 @@
assumptions:
- cofinitary
- left exact
mapped_assumptions:
associated_assumptions:
domain:
- finitely complete
conclusions:
Expand All @@ -65,7 +65,7 @@
assumptions:
- cofinitary
- preserves finite products
mapped_assumptions:
associated_assumptions:
domain:
- finite products
conclusions:
Expand Down Expand Up @@ -99,7 +99,7 @@
assumptions:
- preserves equalizers
- preserves finite products
mapped_assumptions:
associated_assumptions:
domain:
- finite products
conclusions:
Expand Down Expand Up @@ -128,7 +128,7 @@
assumptions:
- preserves coreflexive equalizers
- preserves binary products
mapped_assumptions:
associated_assumptions:
domain:
- binary products
conclusions:
Expand All @@ -139,7 +139,7 @@
- id: mono-preserving_criterion
assumptions:
- preserves regular monomorphisms
mapped_assumptions:
associated_assumptions:
domain:
- mono-regular
conclusions:
Expand All @@ -150,7 +150,7 @@
- id: regular-mono-preserving_criterion
assumptions:
- preserves monomorphisms
mapped_assumptions:
associated_assumptions:
codomain:
- mono-regular
conclusions:
Expand All @@ -161,7 +161,7 @@
- id: another_regular-mono-preserving_criterion
assumptions:
- preserves coreflexive equalizers
mapped_assumptions:
associated_assumptions:
domain:
- pushouts
conclusions:
Expand All @@ -172,7 +172,7 @@
- id: zero_preserving_condition
assumptions:
- preserves terminal objects
mapped_assumptions:
associated_assumptions:
domain:
- pointed
codomain:
Expand All @@ -185,7 +185,7 @@
- id: biproduct_preserving_condition
assumptions:
- preserves finite coproducts
mapped_assumptions:
associated_assumptions:
domain:
- biproducts
codomain:
Expand Down Expand Up @@ -233,7 +233,7 @@

- id: trivial_functors_continuous
assumptions: []
mapped_assumptions:
associated_assumptions:
codomain:
- trivial
conclusions:
Expand All @@ -243,7 +243,7 @@

- id: automatically_preserve_equalizers
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- regular-subobject-trivial
conclusions:
Expand All @@ -254,7 +254,7 @@
- id: trivial_coreflexive_equalizer_preservation
# TODO: rework this once we add "split-epi-trivial"
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- regular-quotient-trivial
conclusions:
Expand All @@ -264,7 +264,7 @@

- id: thin_binary_product_preservation
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- thin
- semi-strongly connected
Expand Down
20 changes: 10 additions & 10 deletions database/data/functor-implications/misc.yaml
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Expand Up @@ -11,7 +11,7 @@
assumptions:
- conservative
- preserves equalizers
mapped_assumptions:
associated_assumptions:
domain:
- equalizers
conclusions:
Expand All @@ -30,7 +30,7 @@
- id: faithful_with_balanced_domain
assumptions:
- faithful
mapped_assumptions:
associated_assumptions:
domain:
- balanced
conclusions:
Expand Down Expand Up @@ -101,7 +101,7 @@

- id: surjective_functor_to_core_connected_category
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- inhabited
codomain:
Expand All @@ -113,7 +113,7 @@

- id: right_invertible_functor_to_trivial_category
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- inhabited
codomain:
Expand All @@ -126,7 +126,7 @@
- id: full_functor_to_trivial_category
# TODO: add the converse once we have category_conclusions
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- strongly connected
codomain:
Expand All @@ -138,7 +138,7 @@

- id: functor_conservative_on_groupoids
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- groupoid
conclusions:
Expand All @@ -148,7 +148,7 @@

- id: automatic_ess_injective_functors
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- core-connected
conclusions:
Expand All @@ -158,7 +158,7 @@

- id: automatic_full_on_isos_functors
assumptions: []
mapped_assumptions:
associated_assumptions:
domain:
- core-connected
codomain:
Expand All @@ -172,7 +172,7 @@
# TODO: rework this once we add "split-mono trivial"
assumptions:
- dominant
mapped_assumptions:
associated_assumptions:
codomain:
- regular-subobject-trivial
conclusions:
Expand All @@ -182,7 +182,7 @@

- id: automatic_preserves_mono
assumptions: []
mapped_assumptions:
associated_assumptions:
codomain:
- left cancellative
conclusions:
Expand Down
2 changes: 1 addition & 1 deletion database/data/functor-implications/monadic.yaml
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Expand Up @@ -13,7 +13,7 @@
- right adjoint
- conservative
- preserves reflexive coequalizers
mapped_assumptions:
associated_assumptions:
domain:
- reflexive coequalizers
conclusions:
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/abelianization.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: Ab
description: This functor maps a group $G$ to its abelianization $G^{\ab} \coloneqq G/[G,G]$.
nlab_link: https://ncatlab.org/nlab/show/abelianization
left_adjoint: null
right_adjoint: forget_abelian

tags:
- algebra
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/binary_coproduct_sets.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: Set
description: This functor maps a pair of sets $(X,Y)$ to their coproduct $X + Y$. It is an example of a right-invertible left adjoint functor which is not a reflector.
nlab_link: null
left_adjoint: null
right_adjoint: diagonal_sets

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/binary_product_sets.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: Set
description: This functor maps a pair of sets $(X,Y)$ to their product $X \times Y$. It is an example of a right-invertible right adjoint functor which is not a coreflector.
nlab_link: null
left_adjoint: diagonal_sets
right_adjoint: null

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/brauer_group.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: Ab
description: The Brauer group $\Br(K)$ of a field $K$ consists of equivalence classes of central simple algebras over $K$, where $A \sim B$ iff $A \otimes_K M_n(K) \cong B \otimes_K M_n(K)$ for some $n \geq 0$. The group structure is given by $[A] \cdot [B] \coloneqq [A \otimes_K B]$, $1 \coloneqq [K]$ and $[A]^{-1} \coloneqq [A^{\op}]$. A homomorphism $K \to L$ induces the homomorphism $\Br(K) \to \Br(L)$ defined by $[A] \mapsto [A \otimes_K L]$.
nlab_link: https://ncatlab.org/nlab/show/Brauer+group
left_adjoint: null
right_adjoint: null

tags:
- algebra
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/continuous-functions.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: CAlg(R) # TODO: specify that R is IR
description: 'This functor maps a topological space $X$ to the commutative $\IR$-algebra $C(X)$ of continuous functions $X \to \IR$. A continuous map $f : X \to Y$ is mapped to the algebra homomorphism $f^* : C(Y) \to C(X)$, $u \mapsto u \circ f$.'
nlab_link: null
left_adjoint: null
right_adjoint: null

tags:
- topology
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/countable_copower_sets.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Set
description: This functor maps a set $X$ to the product $\IN \times X$, which can also be seen as the copower $\IN \otimes X = \coprod_{n \in \IN} X$. It is an example of a polynomial functor.
nlab_link: null
left_adjoint: null
right_adjoint: sequences_sets

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/diagonal_sets.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: SetxSet
description: 'Every category $\C$ has a (binary) diagonal functor $\Delta : \C \to \C^2$, $X \mapsto (X,X)$. Here, we specify that $\C$ is the category of sets.'
nlab_link: https://ncatlab.org/nlab/show/diagonal+functor
left_adjoint: binary_coproduct_sets
right_adjoint: binary_product_sets

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/discrete_topology.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Top
description: This functor maps a set $X$ to the discrete topological space $D(X) \coloneqq (X, P(X))$ in which every subset is open. It is a typical example of a fully faithful functor that preserves finite but does not preserve infinite products.
nlab_link: https://ncatlab.org/nlab/show/discrete+and+indiscrete+topology
left_adjoint: null
right_adjoint: forget_topology

tags:
- topology
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/doubling_sets.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Set
description: This functor maps a set $X$ to its double $2 X \coloneqq X + X$. It is a simple example of a polynomial functor.
nlab_link: null
left_adjoint: null
right_adjoint: squaring_sets

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/empty_sets.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Set
description: 'Every category $\C$ has a unique functor $!_{\C} : \varnothing \to \C$. Here, we specify $\C = \Set$, but most of the properties do not depend on the choice of $\C$, as long as $\C$ is non-empty. This is the simplest example of a functor to $\Set$ that is both continuous and cocontinuous, but is neither representable nor a left or right adjoint.'
nlab_link: null
left_adjoint: null
right_adjoint: null

tags:
- set theory
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/enveloping_group.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Grp
description: 'This functor maps a monoid $M$ to the group $F(M)$ that is equipped with a universal homomorphism $i_M : M \to F(M)$. It is called the (universal) enveloping group or the group completion of $M$; in the commutative case, it is known as the Grothendieck group of $M$. As a possible construction of $F(M)$, take the free group on generators $\underline{m}$ for $m \in M$ subject to the relations $\underline{1} = 1$ and $\underline{m \cdot n} = \underline{m} \cdot \underline{n}$.'
nlab_link: https://ncatlab.org/nlab/show/free+functor
left_adjoint: null
right_adjoint: forget_inverses

tags:
- algebra
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/forget_abelian.yaml
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Expand Up @@ -6,6 +6,7 @@ codomain: Grp
description: This functor maps an abelian group to itself, considered merely as a group.
nlab_link: https://ncatlab.org/nlab/show/forgetful+functor
left_adjoint: abelianization
right_adjoint: null

tags:
- algebra
Expand Down
1 change: 1 addition & 0 deletions database/data/functors/forget_addition.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ codomain: Mon
description: This functor maps a ring to its underlying multiplicative monoid, which as "forgotten" the addition of the ring.
nlab_link: https://ncatlab.org/nlab/show/forgetful+functor
left_adjoint: monoid_ring
right_adjoint: null

tags:
- algebra
Expand Down
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