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nLab > Latest Changes: Barr's theorem

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    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeApr 8th 2011

    created stub for Barr’s theorem (If a statement in geometric logic is deducible from a geometric theory using classical logic and the axiom of choice, then it is also deducible from it in constructive mathematics.)

    • CommentRowNumber2.
    • CommentAuthorzskoda
    • CommentTimeApr 8th 2011
    Just a reminder. There is also another theorem sometimes referred as Barr's theorem, or more precisely, the Barr embedding theorem.
    • CommentRowNumber3.
    • CommentAuthorThomas Holder
    • CommentTimeMay 9th 2020

    Expanded a bit on the eliminability of non-constructive proofs with respect to geometric theories and sequents.

    diff, v9, current

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