Quotients by ${\bf C}\sp\ast \times{\bf C}\sp\ast$ actions
نویسندگان
چکیده
منابع مشابه
Quotients by non-reductive algebraic group actions
Geometric invariant theory (GIT) was developed in the 1960s by Mumford in order to construct quotients of reductive group actions on algebraic varieties and hence to construct and study a number of moduli spaces, including, for example, moduli spaces of bundles over a nonsingular projective curve [26, 28]. Moduli spaces often arise naturally as quotients of varieties by algebraic group actions,...
متن کاملTorus actions on compact quotients
For a reductive Lie group G and a uniform lattice Γ in G we consider the compact space Γ\G. We fix a maximal torus H in G and consider its action on the compact quotient Γ\G. Assuming H to be noncompact we will prove a Lefschetz formula relating compact orbits as local data to the action of the torus H on a global cohomology theory (tangential cohomology). The compact orbits are parametrized mo...
متن کاملQ-Exact Actions for BF Theories
The actions for all classical (and consequently quantum) BF theories on n-manifolds is proven to be given by anti-commutators of hermitian, nilpotent, scalar fermionic charges with Grassmann-odd functionals. In order to show this, the space of fields in the theory must be enlarged to include “mass terms” for new, non-dynamical, Grassmann-odd fields. The implications of this result on observable...
متن کاملGeometric Quotients of Unipotent Group Actions
This article is devoted to the problem of constructing geometric quotients of a quasiaffine scheme X over a field of characteristic 0 by a unipotent algebraic group G. This problem arises naturally if one tries to construct moduli spaces in the sense of Mumford's 'geometric invariant theory' for singularities of algebraic varieties or for modules over the local ring of such a singularity. Indee...
متن کاملFactorial Algebraic Group Actions and Categorical Quotients
Given an action of an affine algebraic group with only trivial characters on a factorial variety, we ask for categorical quotients. We characterize existence in the category of algebraic varieties. Moreover, allowing constructible sets as quotients, we obtain a more general existence result, which, for example, settles the case of a finitely generated algebra of invariants. As an application, w...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 1985
ISSN: 0002-9947
DOI: 10.1090/s0002-9947-1985-0784002-8