The relative Clemens Conjectures for $\frac{1}{2}$-log Calabi-Yau threefolds

Fuente: arXiv
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Main Author: Aguilar, Rodolfo
Format: Preprint
Published: 2026
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_version_ 1866912938169729024
author Aguilar, Rodolfo
author_facet Aguilar, Rodolfo
contents We formulate a relative analogue of the Clemens conjectures for 1/2-log Calabi-Yau threefold pairs (X,Y) (where K_X+2Y is isomorphic to O_X). This framework rests on the restoration of a perfect deformation/obstruction duality specific to the 1/2-log CY threefold setting. Based on this duality, we conjecture that for a generic intersection configuration on the boundary divisor Y, the number of rational curves anchored to these points is finite, and every such curve possesses the balanced relative normal bundle N_{C/X}(-Y) isomorphic to O_C(-1) + O_C(-1). In a joint appendix with Adrian Zahariuc, we verify this framework for prime Fano threefolds of index two. Using specialization techniques, we demonstrate that the usual virtual complications of relative Gromov-Witten theory are naturally suppressed in this setting. This trivialization of the relative moduli space cleanly reduces the virtual invariants to honest, classical enumerative counts, thereby rigorously proving the geometric conjecture.
format Preprint
id arxiv_https___arxiv_org_abs_2601_11813
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The relative Clemens Conjectures for $\frac{1}{2}$-log Calabi-Yau threefolds
Aguilar, Rodolfo
Algebraic Geometry
14N35, 14J30, 14J45, 14N10
We formulate a relative analogue of the Clemens conjectures for 1/2-log Calabi-Yau threefold pairs (X,Y) (where K_X+2Y is isomorphic to O_X). This framework rests on the restoration of a perfect deformation/obstruction duality specific to the 1/2-log CY threefold setting. Based on this duality, we conjecture that for a generic intersection configuration on the boundary divisor Y, the number of rational curves anchored to these points is finite, and every such curve possesses the balanced relative normal bundle N_{C/X}(-Y) isomorphic to O_C(-1) + O_C(-1). In a joint appendix with Adrian Zahariuc, we verify this framework for prime Fano threefolds of index two. Using specialization techniques, we demonstrate that the usual virtual complications of relative Gromov-Witten theory are naturally suppressed in this setting. This trivialization of the relative moduli space cleanly reduces the virtual invariants to honest, classical enumerative counts, thereby rigorously proving the geometric conjecture.
title The relative Clemens Conjectures for $\frac{1}{2}$-log Calabi-Yau threefolds
topic Algebraic Geometry
14N35, 14J30, 14J45, 14N10
url https://arxiv.org/abs/2601.11813