Pith. sign in

REVIEW 5 cited by

Relative topos theory via stacks

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 2107.04417 v1 pith:5YTBCNV6 submitted 2021-07-09 math.AG math.CT

classification math.AGmath.CT
keywords toposrelativesheavessitestackstheoryallowsadjunction
verification ladder T0 review T1 audit T2 compute T3 formal
0 comments
abstract

We introduce new foundations for relative topos theory based on stacks. One of the central results in our theory is an adjunction between the category of toposes over the topos of sheaves on a given site $({\mathcal{C}}, J)$ and that of ${\mathcal{C}}$-indexed categories. This represents a wide generalization of the classical adjunction between presheaves on a topological space and bundles over it, and allows one to interpret several constructions on sheaves and stacks in a geometrical way; in particular, it leads to fibrational descriptions of direct and inverse images of sheaves and stacks, as well as to a geometric understanding of the sheafification process. It also naturally allows one to regard any Grothendieck topos as a 'petit' topos associated with a 'gros' topos, thereby providing an answer to a problem posed by Grothendieck in the seventies. Another key ingredient in our theory is a notion of relative site, which allows one to represent arbitrary geometric morphisms towards a fixed base topos of sheaves on a site as structure morphisms induced by relative sites over that site.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 5 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Generation of Grothendieck topologies, provability and operations on subtoposes

    math.CT 2025-08 conditional novelty 6.0 of 10

    A systematic study of subtoposes yields explicit formulas for generating Grothendieck topologies and new preservation theorems for pullbacks of subtoposes.

  2. Sheaves on a bicategory

    math.CT 2025-07 conditional novelty 6.0 of 10

    The paper proves a general adjunction between complete B-categories and 2-presheaves on Map(B), recovering sheaf theory over quantaloids and enrichment over monoidal categories as special cases.

  3. Local fibrations and morphisms of relative toposes

    math.CT 2025-07 conditional novelty 6.0 of 10

    Local fibrations, defined using Grothendieck topologies, characterize the site-level functors that give morphisms of relative toposes and support a weak indexed Diaconescu theorem.

  4. Stackification via adjunction

    math.CT 2025-05 reject novelty 6.0 of 10

    A 2-adjunction between indexed categories and 2-toposes is claimed to compute stackification as the composite Γ∘Λ.

  5. Sites and Grothendieck toposes: an introduction

    math.CT 2025-08 unverdicted

    An expository book excerpt: it restates standard category theory and sheaf background as preparation for a planned introduction to Grothendieck toposes, with no new mathematical results.

Pith tools