English

Mixed Hodge Modules and Canonical Perverse Extensions for Multi-Node Conifold Degenerations

Algebraic Geometry 2026-04-13 v2 Category Theory

Abstract

We study one-parameter conifold degenerations whose central fiber has finitely many ordinary double points and construct a mixed-Hodge-module refinement of the canonical corrected perverse object associated with the degeneration. We build a rank-one point-supported mixed-Hodge-module block at each node, identify the global singular quotient as k=1rik\Q{pk}H(1)\bigoplus_{k=1}^r i_{k*}\Q^H_{\{p_k\}}(-1), and assemble these local blocks via Saito's divisor-case gluing formalism into a global object PHMHM(X0)\mathcal P^H \in MHM(X_0). We prove that PH\mathcal P^H realizes the corrected perverse object, fits into an exact sequence 0ICX0HPHk=1rik\Q{pk}H(1)00 \to IC^H_{X_0} \to \mathcal P^H \to \bigoplus_{k=1}^r i_{k*}\Q^H_{\{p_k\}}(-1) \to 0, and that the same quotient realizes the finite local vanishing sector in the nearby-cycle formalism. We further relate the mixed-Hodge-module extension, its realized perverse extension, and the induced extension on hypercohomology carrying the limiting mixed Hodge structure. This gives a theorem-level Hodge-theoretic refinement of the corrected perverse extension in the finite multi-node ordinary double point setting.

Keywords

Cite

@article{arxiv.2604.05367,
  title  = {Mixed Hodge Modules and Canonical Perverse Extensions for Multi-Node Conifold Degenerations},
  author = {Abdul Rahman},
  journal= {arXiv preprint arXiv:2604.05367},
  year   = {2026}
}

Comments

Added local/global V-filtration admissibility clarifications, strengthened Saito gluing proofs, tightened rigidity arguments, and substantially trimmed introductory and concluding prose

R2 v1 2026-07-01T11:56:32.302Z