Kollár–Pardon classification of semialgebraic universal covers

For a connected normal complex projective variety, is its universal cover biholomorphic to a semialgebraic open subset of a projective variety exactly when it has the form D×Cᵐ×F, with D bounded symmetric and F simply connected normal projective?

Why it matters and what counts as progress

Why it matters: It seeks a geometric classification of normal projective universal covers admitting a semialgebraic realization.

What counts as progress: Prove both directions of the semialgebraic universal-cover classification for normal projective varieties, with the product factors as stated.

How the problem developed

  1. 12 Apr 2011 · Foundational result [1]

    János Kollár and John Pardon Studied projective varieties with semialgebraic universal covers, providing the prior work from which the later product-classification conjecture arose.

  2. 24 Sept 2026 · Classification [2]

    OpenAI Reported the iff classification for connected normal projective complex varieties: the universal cover has the stated semialgebraic form exactly for products of a bounded symmetric domain, affine space, and a simply connected normal projective variety.

AI contribution

Sources

  1. János Kollár and John Pardon, Algebraic varieties with semialgebraic universal cover
  2. OpenAI, Semialgebraic universal covers of normal projective varieties
  3. Semialgebraic universal covers of normal projective varieties
  4. Semialgebraic universal covers of normal projective varieties
  5. OpenAI mathematics release account
  6. Lean scope note for bounded-domain symmetry
  7. Lean bounded-domain symmetry proof
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