quillen suggested to his student kenneth brown that it might be possible to create a theory of sheaves of spectra of which "k"-theory would provide an example. the sheaf of "k"-theory spectra would, to each open subset of a variety, associate the "k"-theory of that open subset. brown developed such a theory for his thesis. simultaneously, gersten had the same idea. at a seattle conference in autumn of 1972, they together discovered a spectral sequence converging from the sheaf cohomology of formula_10, the sheaf of "k"-groups on "x", to the "k"-group of the total space. this is now called the brown–gersten spectral sequence.