I am a professor of the math department of Kyushu university. I study gauge theory, Floer theory, geometry and topology.
Email : hsasahira[at]math.kyushu-u[dot]ac.jp
Papers (since 2015)
Seiberg-Witten Floer spectra for b_1 > 0 , the Memoirs of the European Mathematical Society, vol.17, 2025 (with Matthew Stoffregen)
Unfolded Seiberg-Witten Floer spectra, II: relative invariants and the gluing theorem , J. Differential Geom. 124 (2023), no. 2, 231–316 (with Tirasan Khandhawit, Jianfeng Lin)
Twisted Donaldson invariants, Math. Proc. Cambridge Philos. Soc. 171 (2021), no. 3, 515–568 (with Tsuyoshi Kato, Hang Wang)
Unfolded Seiberg-Witten Floer spectra, I: Definition and invariance, Geom. Topol. 22 (2018), no. 4, 2027–2114 (with Tirasan Khandhawit, Jianfeng Lin)
Stable cohomotopy Seiberg-Witten invariants of connected sums of four-manifolds with positive first Betti number II: Applications, Comm. Anal. Geom. 25 (2017), no. 2, 373–393 (with Masashi Ishida).
Stable cohomotopy Seiberg-Witten invariants of connected sums of four-manifolds with positive first Betti number, I: non-vanishing theorem, Internat. J. Math. 26 (2015), no. 6, 1541004, 23 pp (with Masashi Ishida).
Preprints
Lattice homology and Seiberg-Witten-Floer spectra, preprint 2023 (with Irving Dai, Matthew Stoffregen)