Comparison of conformal blocks with H^0 of the semistable-modification extension beyond the rational case

Determine whether, for a general vertex operator algebra V (beyond the rational case), the spaces of conformal blocks obtained by extending the sheaf of coinvariants to the boundary via the semistable-modification approach (as in the construction of the extended sheaf over the universal curve) agree with the zeroth cohomology H^0 of the extension of chiral homology constructed using semistable modifications in this paper.

Background

The paper extends chiral/factorization homology to the Deligne–Mumford boundary using semistable modifications and proves gluing formulas, recovering the Verlinde-type behavior at the level of H0 under finiteness assumptions. Classical extensions of conformal blocks to the boundary for vertex operator algebras were constructed in prior work (e.g., by extending the sheaf over \bar{X}g via identification with \bar{M}{g,1}).

While this new extension provides a multi-point and derived framework, the authors do not know if the resulting conformal blocks coincide with the H0 of their extension outside the rational VOA setting, leaving the general comparison problem open.

References

However, we do not know whether the resulted spaces of conformal blocks agree with H0 of our extension, beyond the rational case.

Nodal degeneration of chiral algebras  (2603.30037 - Nafcha, 31 Mar 2026) in Introduction, Relation to previous work