Mahowaldean elements, symplectic bordism and framed hypersurfaces
Mahowaldean elements, symplectic bordism and framed hypersurfaces
Zoom link: https://princeton.zoom.us/j/96282936122
Passcode: 998749
In the 1970s Mark Mahowald constructed an infinite family of stable homotopy elements systematically detected in the 2-line of the Adams spectral sequence. I will review the construction then give a modified version which has some good features:
1) These elements map to 0 in the symplectic bordism ring.
2) They are detected by primary operations in symplectic bordism and so are detected in the 1-line of the symplectic bordism Adams-Novikov spectral sequence.
Actually the same can be shown to apply to Mahowald's original elements but this requires slightly different methods.
I will also explain how to construct framed hypersurfaces which represent Mahowald's elements in framed bordism; this uses unstable properties of dual Brown-Gitler spaces proved in the 1990s.