English

Parametrized scissors congruence $K$-theory of manifolds and cobordism categories

Algebraic Topology 2026-04-03 v2 K-Theory and Homology

Abstract

We introduce a parametrized version of scissors congruence KK-theory of manifolds with tangential structure, which includes a topologized version of the scissors congruence KK-theory of oriented manifolds as a special case. We examine the relation of this KK-theory spectrum with cut-and-paste invariants, the (parametrized) cobordism category and with (bivariant) algebraic KK-theory of spaces. We show that the scissors congruence KK-theory of oriented manifolds agrees on π0\pi_0 with a version of the oriented cobordism category where we allow cobordisms to have free boundaries. Lastly, we show that the spectrum level refinement of the Euler characteristic from the scissors congruence KK-theory to K(Z)K(\mathbb{Z}) detects on π1\pi_1 the Kervaire semicharacteristic.

Keywords

Cite

@article{arxiv.2504.01810,
  title  = {Parametrized scissors congruence $K$-theory of manifolds and cobordism categories},
  author = {Mona Merling and George Raptis and Julia Semikina},
  journal= {arXiv preprint arXiv:2504.01810},
  year   = {2026}
}

Comments

39 pages. Added a new section on K_1. Contains several fixes and expository improvements from the first version