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feat(CategoryTheory/Sites): add the Grothendieck topology generated by a precoverage #32652
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PR summary 43dc3a9ad0Import changes for modified filesNo significant changes to the import graph Import changes for all files
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Co-authored-by: Christian Merten <[email protected]>
Co-authored-by: Christian Merten <[email protected]>
chrisflav
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Thanks!
maintainer delegate
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🚀 Pull request has been placed on the maintainer queue by chrisflav. |
Co-authored-by: Christian Merten <[email protected]>
Co-authored-by: Christian Merten <[email protected]>
Add the file
PrecoverageToGrothendieck.lean, in which the Grothendieck topology generated by a precoverage is defined asPrecoverage.toGrothendieck. This replace the previousPrecoverage.toGrothendieck, which was defined only in the case of a precoverage having pullbacks and being stable under base change. The equivalence between the two constructions isPrecoverage.toGrothendieck_toCoverage.Prove
Precoverage.isSheaf_toGrothendieck_iff: given a precoverageJ, a type-valued presheaf is a sheaf forJ.toGrothendieckif and only if it is a sheaf for all the pullback sieves of the presieves inJ. The proof is based on the previous proof ofisSheaf_coverage, which is now a consequence ofPrecoverage.isSheaf_toGrothendieck_iff.