Commit 2026-08-23 14:46 f2916a54

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refactor(CategoryTheory/Sites): split long file Sieves.lean (#43014) Split this file into the following pieces:

  • Presieve.lean — 434 lines — Presieves, arrow families, binding, pullback and pushforward along morphisms, pullback existence, and uncurrying.
  • Basic.lean — 526 lines — Core sieve theory: generation, lattice structure, arrow families, pullbacks, and pushforwards.
  • Functoriality.lean — 438 lines — Pullback, pushforward, and mapping of both presieves and sieves along functors and equivalences.
  • Presheaf.lean — 153 lines — The presheaf associated to a sieve and its inclusion into the Yoneda presheaf.
  • Shrink.lean — 83 lines — Universe-shrunk sieve presheaves and their comparison isomorphisms.

Estimated changes

deleted inductive CategoryTheory.Presieve.map
deleted structure CategoryTheory.Sieve
deleted theorem CategoryTheory.bot_apply
deleted theorem CategoryTheory.top_apply
added structure CategoryTheory.Sieve