Year: 2026
Type: preprint
Abstract: Many perfect obstruction theories and virtual cycles in enumerative geometry are shadows from derived geometry. In this paper, we give a general construction of reduced perfect obstruction theories arising from a geometric reduction of the derived stack $X$ with respect to a $(-1)$-shifted log function $w_α$. Notably, this construction leads to a decomposition of the virtual cycle $[X]^{\mathrm{vir}}$ into the reduced virtual cycle $[X]^{\mathrm{red}}$ and a reduced boundary cycle $[Δ_X]^\red$. Our construction is motivated by future applications to the moduli stack of UMD logarithmic R-maps in log GLSM \cite{CJR21}. Along the way, we develop logarithmic analogs of several constructions in derived geometry, in particular proving a logarithmic Lagrangian intersection theorem.
Source: arXiv (Cornell University)
Authors: Janda, Felix, Li, Ruoxi
Language: English
Subfield: Geometry and Topology
Field: Mathematics
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W7222974074