Zariski-density conjecture for singular hyperbolic metrics

For every non-hyperbolic Riemann surface XX and every singular hyperbolic metric gg on XX in the sense of potential theory, the associated monodromy group Mon(g)PSL(2,R)\operatorname{Mon}(g)\subseteq \operatorname{PSL}(2,\mathbb{R}) is Zariski dense in PSL(2,R)\operatorname{PSL}(2,\mathbb{R}).

Progress summary

Solved

A new unrefereed preprint claims to settle the conjecture, but independent confirmation is not yet available.

The conjecture asserts that monodromy from a singular hyperbolic metric on any non-hyperbolic Riemann surface is Zariski-dense. The original work established many cases but left one subgroup-exclusion step unresolved.

Known results

  • The 2020 preprint proves density for compact surfaces, C\mathbb{C}, C{0}\mathbb{C}\setminus\{0\}, and punctured tori.
  • For arbitrary non-hyperbolic surfaces it excludes monodromy in subgroups conjugate to H2H_{2}, H2H_{2}^{\prime}, H3H_{3}, and L0L_{0}, reducing the problem to the subgroup LL.
  • The thrice-punctured sphere remains outside that argument because its maximal abelian cover is hyperbolic.

August 2026 claimed completion

A new preprint claims that the remaining parabolic-surface obstruction has been ruled out, completing the conjecture in arbitrary non-hyperbolic cases. This is a claim from an unrefereed preprint, not yet an independently verified result.

Current status (as of August 2026): the conjecture has a claimed complete proof, but its validity remains unverified; absent confirmation, the final subgroup-exclusion step is not settled.

Sources
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Solutions 0

No solutions have been posted yet.