3 papers
math.AT2026
Hyperkähler bases for six rational bordism theories
Jonathan Buchanan, Arun Debray, Cameron Krulewski +1
We use tori and Hilbert schemes of K3 surfaces to construct explicit bases for the real, complex, and quaternionic versions of rational symplectic and rational Spin bordism. The ke…
math.AG2025
Quadratic counts of highly tangent lines to hypersurfaces
Stephen McKean, Giosuè Muratore, Wern Juin Gabriel Ong
We give two geometric interpretations for the local type of a line that is highly tangent to a hypersurface in a single point. One interpretation is phrased in terms of the Wronski…
math.AT2025
KSp-characteristic classes determine Spin cobordism
Jonathan Buchanan, Stephen McKean
A classic result of Anderson, Brown, and Peterson states that the cobordism spectrum MSpin (respectively, MSpin) splits as a sum of Eilenberg--Mac Lane spectra and connective c…