Displaying 881 – 900 of 902

Showing per page

Cyclotomic modular lattices

Eva Bayer-Fluckiger (2000)

Journal de théorie des nombres de Bordeaux

Several interesting lattices can be realised as ideal lattices over cyclotomic fields : some of the root lattices, the Coxeter-Todd lattice, the Leech lattice, etc. Many of these are modular in the sense of Quebbemann. The aim of the present paper is to determine the cyclotomic fields over which there exists a modular ideal lattice. We then study an especially simple class of lattices, the ideal lattices of trace type. The paper gives a complete list of modular ideal lattices of trace type defined...

Cyclotomic quadratic forms

François Sigrist (2000)

Journal de théorie des nombres de Bordeaux

Voronoï ’s algorithm is a method for obtaining the complete list of perfect n -dimensional quadratic forms. Its generalization to G -forms has the advantage of running in a lower-dimensional space, and furnishes a finite, and complete, classification of G -perfect forms ( G is a finite subgroup of G L ( n , ) ) . We study the standard, φ ( m ) -dimensional irreducible representation of the cyclic group C m of order m , and give the, often new, densest G -forms. Perfect cyclotomic forms are completely classified for φ ( m ) < 16 and for...

Currently displaying 881 – 900 of 902