Columbia subject headings:
Homology theory.
Homotopy theory.
Rings (Algebra)
Spectral theory (Mathematics)
Harvard subject headings:
Homology theory.
Homotopy theory.
Rings (Algebra)
Spectral theory (Mathematics)
Princeton subject headings:
Homology theory.
Homotopy theory.
Rings (Algebra)
Spectral theory (Mathematics)