Measure theory 1.3.2: fix TFAE Lebesgue strength from issue #517#523
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teorth merged 1 commit intoJun 15, 2026
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Use LebesgueMeasurable preimages in RealMeasurable.TFAE and ComplexMeasurable.TFAE to match the unsigned TFAE list. Co-authored-by: Cursor <cursoragent@cursor.com>
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Fixes part of #517
Bug
RealMeasurable.TFAEandComplexMeasurable.TFAEusedMeasurableSetfor open/closed preimages, which is Borel strength onEuclideanSpace' d, while conditions (1)–(3) are Lebesgue-strength.Root cause
Conditions (4)/(5) copied Mathlib's Borel
MeasurableSetinstead of the project'sLebesgueMeasurable, unlikeUnsignedMeasurable.TFAE.Why this fix is correct
A Lebesgue-measurable function can have a non-Borel preimage of an open set, so (1) does not imply the old (4). Matching the unsigned TFAE list restores a consistent equivalence chain.
Test plan
lake buildMade with Cursor