Inspired in part by Matsumoto's theorem, Milnor made a definition of the higher "K"-groups of a field. He referred to his definition as "purely "ad hoc"", and it neither appeared to generalize to all rings nor did it appear to be the correct definition of the higher "K"-theory of fields. Much later, it was discovered by Nesterenko and Suslin and by Totaro that Milnor "K"-theory is actually a direct summand of the true "K"-theory of the field. Specifically, "K"-groups have a filtration called the "weight filtration", and the Milnor "K"-theory of a field is the highest weight-graded piece of the "K"-theory. Additionally, Thomason discovered that there is no analog of Milnor "K"-theory for a general variety.