Fundamental theorem of algebraic K-theory

In algebra, the fundamental theorem of algebraic K-theory describes the effects of changing the ring of K-groups from a ring R to ${\displaystyle R[t]}$ or ${\displaystyle R[t,t^{-1}]}$. The theorem was first proved by Hyman Bass for ${\displaystyle K_{0},K_{1}}$ and was later extended to higher K-groups by Daniel Quillen.