We prove some fundamental results like localization, excision,
Nisnevich descent, and the regular blow-up formula for the algebraic
-theory of certain
stack quotients of schemes with affine group scheme actions. We show that the homotopy
-theory of
such stacks is homotopy invariant. This implies a similar homotopy invariance property of the
algebraic
-theory
with coefficients.
Keywords
algebraic $K\mskip-2mu$-theory, singular schemes, groups
actions, stacks