Analytic sets

Capacitability, a non-Borel witness, and the separation it settles.

• MTH.C-2026-6013krappWirthSeparationMeasTarget_holds

  The Krapp–Wirth measurable-target separation holds unconditionally: the analytic non-Borel witness discharges the hypothesis of analytic_nonborel_set_gives_measTarget_separation.

• MTH.C-2026-6018MeasureTheory.AnalyticSet.cap_eq_iSup_isCompact

  Choquet capacitability. For analytic sets, capacity equals the supremum over compact subsets (Kechris 30.13).

• MTH.C-2026-6023MeasureTheory.exists_analyticSet_not_measurableSet_real

  An analytic non-Borel subset of ℝ: the image of the Baire-space witness under the continuous injection. Analyticity transfers along the continuous image; non-Borelness transfers back along the injective preimage.