Spectral schemes as ringed lattices

Generalized Ringed Spaces and Schemes

Elimination schemes and lattices

Perfect vertex elimination schemes are part of the characterizations for several classes of graphs, including chordal and cop-win. Partial elimination schemes reduce a graph to an important subgraph, for example, k-cores and robber-win graphs. We are interested in those partial elimination schemes, in which once a vertex can be eliminated it is always ready to be eliminated. In such a scheme, t...

On the Cyclic Homology of Ringed Spaces and Schemes

We prove that the cyclic homology of a scheme with an ample line bundle coincides with the cyclic homology of its category of algebraic vector bundles. As a byproduct of the proof, we obtain a new construction of the Chern character of a perfect complex on a ringed space. 1991 Mathematics Subject Classi cation: Primary: 16E40; Secondary: 18E30, 14F05.

On the Cylic Homology of Ringed Spaces and Schemes

In their recent proof [2] of Schapira-Schneider’s conjecture [19], Bressler-Nest-Tsygan construct a (generalized) Chern character from the Ktheory of perfect complexes to the negative cyclic homology HC− ∗ (A) of a sheaf of algebras A on a topological space. The first aim of this paper is to show how to construct a (classical) Chern character defined on the Grothendieck group of perfect complex...

Spectral Thinning in GLD Lattices

This paper deals with generalized low-density (GLD) lattices which have been recently shown to be an excellent family of lattices for communication over the Gaussian channel. Under iterative decoding, numerical results for GLD lattices show an error rate per lattice coordinate extremely close to Poltyrev theoretical limit of an infinite constellation. These results are found for GLD ensembles w...