Intrinsic Non-Reductive Geometric Invariant Theory and Moduli Spaces of Principal Bundles with Non-Reductive Structure Groups

George Cooper, Ludvig Modin

We prove the existence of moduli spaces for algebraic stacks with a weak action of $\Theta =[{\mathbb{A}}^1/{\mathbb{G}}_m]$ (including stacks of filtered objects and unstable $\Theta$-strata) f…