$\mathbb{K}$-framings and $\mathbb{K}$-quadratic forms on surfaces
Abstract
We introduce the notions of -framings, based -framings and relative -framings of a compact connected oriented surface for any commutative ring with unit, and a map which maps a based loop on to a homology class of its unit tangent bundle , which recovers Johnson's lifting in the case . This generalizes the correspondence between a quadratic form and a spin structure established by Johnson to any commutative ring with unit. If the genus of is positive, we have a bijection between the set of -framings and the set of some twisted cocycles of the mapping class group of the surface . Through this bijection, in the case where the boundary is non-empty and connected, we discuss some relation between -framings and the extended first Johnson homomorphism.
Cite
@article{arxiv.2604.27531,
title = {$\mathbb{K}$-framings and $\mathbb{K}$-quadratic forms on surfaces},
author = {Nariya Kawazumi},
journal= {arXiv preprint arXiv:2604.27531},
year = {2026}
}