Hilbert scheme

Abstract: In his investigations of the mathematical foundations of quantum mechanics, Mackey1 has proposed the following problem: Determine all measures on the closed subspaces of a Hilbert space. A measure on the closed subspaces means a function μ which assigns to every closed subspace a non-negative real number such that if {Ai} is a countable collection of mutually orthogonal subspaces having closed linear span B, then $$ \mu (B) = \sum {\mu \left( {{A_i}} \right)} $$ .

Abstract: T n "0 We shall denote by Cf and C$ the closed linear manifolds spanned by { f}o and {T*'g}o, respectively; f , g being elements in H. This study is devoted to two general problems concerning the transformations T and T* which we shall call the extinction problem and the closure problem. We shall say that T has an extinction theorem if, for every f # o, it is true that the manifold Cj contains at least one eigenelement 9 # o. In the ease

Abstract: We discuss the Gromov–Witten/Donaldson–Thomas correspondence for 3-folds in both the absolute and relative cases. Descendents in Gromov–Witten theory are conjectured to be equivalent to Chern characters of the universal sheaf in Donaldson–Thomas theory. Relative constraints in Gromov–Witten theory are conjectured to correspond in Donaldson–Thomas theory to cohomology classes of the Hilbert scheme of points of the relative divisor. Independent of the conjectural framework, we prove degree 0 formulas for the absolute and relative Donaldson–Thomas theories of toric varieties.