Real Orientations, Real Gromov-Witten Theory, and Real Enumerative Geometry

TL;DR

This paper develops a comprehensive real Gromov-Witten theory for various symplectic manifolds, establishing orientations on moduli spaces and connecting to real enumerative geometry, including applications to odd-dimensional projective spaces and the quintic threefold.

Contribution

It introduces a novel orientation principle for real Gromov-Witten moduli spaces, extending the theory to arbitrary genera and ensuring compatibility across boundaries.

Findings

Constructed real Gromov-Witten invariants for many manifolds.

Established natural orientations on moduli spaces of real maps.

Connected the theory with real enumerative geometry and topology.

Abstract

The present note overviews our recent construction of real Gromov-Witten theory in arbitrary genera for many real symplectic manifolds, including the odd-dimensional projective spaces and the renowned quintic threefold, its properties, and its connections with real enumerative geometry. Our construction introduces the principle of orienting the determinant of a differential operator relative to a suitable base operator and a real setting analogue of the (relative) spin structure of open Gromov-Witten theory. Orienting the relative determinant, which in the now-standard cases is canonically equivalent to orienting the usual determinant, is naturally related to the topology of vector bundles in the relevant category. This principle and its applications allow us to endow the uncompactified moduli spaces of real maps from symmetric surfaces of all topological types with natural orientations and to verify that they extend across the codimension-one boundaries of these spaces, thus implementing a far-reaching proposal from C.-C. Liu's thesis.