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Construction junctions are diamonds. They show where multiple structures must coexist on the same carrier and satisfy compatibility conditions.
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This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID
e_site_topos
Relation type
Canonical construction canonical-construction
Direction
source → target
Endpoint roles
source: Canonically constructs; target: Canonically constructed from
Authored annotation
form the sheaf topos
Authored explanation
Form Sh(C,J), the category of sheaves of sets on the site. This is a canonical construction from a site, not an equivalence between the site and the resulting topos.
How to interpret this relation type
Apply a standard functorial or canonical construction whose output is not merely a reduct of the input and is not generally an equivalent presentation of the same object.
This is an authored directed relation from the source endpoint to the target endpoint.
Relation ID
grothendieck_topos_to_elementary_topos_reduct
Relation type
Induced / forgotten induced-forgotten
Direction
source → target
Endpoint roles
source: Yields by induction / forgetting; target: Obtained by induction / forgetting from
Authored annotation
retain elementary-topos structure
Authored explanation
A Grothendieck topos has finite limits, exponentials, and a subobject classifier.
How to interpret this relation type
Pass canonically from a stronger object to structure it determines, or forget part of the data while retaining a valid weaker structure. The carrier may change under a canonical induced construction.