Analytic Bertini restriction for multiplier ideals

For a plurisubharmonic weight on a product of polydiscs, does the ambient multiplier ideal restrict to the fibre multiplier ideal outside a pluripolar parameter set? This asks for a smaller exceptional set than a merely Lebesgue-null set.

Why it matters and what counts as progress

Why it matters: Replacing a null exceptional set by a pluripolar one gives a stronger analytic description of where multiplier-ideal restriction can fail.

What counts as progress: Prove the pluripolar exceptional-set bound in the local setting or extend the restriction theorem to holomorphic fibrations.

How the problem developed

  1. 1987 · Theorem [1][3]

    Takeo Ohsawa and Kenshō Takegoshi Established an L² extension theorem that yields one inclusion in the restriction formula for multiplier ideals on fibres.

  2. 2022 · Partial result [2][3]

    Mingchen Xia Proved an analytic Bertini restriction result for projective fibrations, leaving the local case open.

  3. 28 Jul 2026 · Reported claim [3]

    Mingchen Xia, with GPT-5.6 Sol proof work Proved equality of ambient and fibre multiplier ideals outside a pluripolar parameter set in the local setting and for holomorphic fibrations.

AI contribution

Sources

  1. On the extension of L2 holomorphic functions
  2. Analytic Bertini theorem
  3. Xia, Analytic Bertini theorem II: The local case
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