Inter-universal geometry と ABC予想 (応援スレ) 76

Since the extensive calculations of stable homotopy groups of spheres in the 1960s,
algebraic topologists have recognized the extreme complexity of stable homotopy theory.
...
However, the most surprising and important general result on these classes came in 1989
when Tetsusuke Ohkawa demonstrated that they just form a set and thus an actual lattice.
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Chicago, USA 2016 A. K. Bousfield