Narrow your search

Library

KBR (3)

KU Leuven (3)

UAntwerpen (3)

UGent (3)

VUB (3)

UCLouvain (2)

ULB (1)

ULiège (1)

UNamur (1)


Resource type

book (4)


Language

English (4)


Year
From To Submit

1999 (1)

1993 (1)

1988 (1)

1976 (1)

Listing 1 - 4 of 4
Sort by

Book
Sphere packings, lattices and groups
Authors: --- ---
ISBN: 0387979123 3540979123 1475722516 1475722494 Year: 1993 Volume: vol 290 Publisher: New York Berlin Paris Tokyo Springer

Sphere packings, lattices and groups
Authors: --- ---
ISBN: 0387985859 9780387985855 1441931341 1475765681 Year: 1999 Volume: 290 Publisher: New York Berlin Paris Tokyo Springer

Loading...
Export citation

Choose an application

Bookmark

Abstract

We now apply the algorithm above to find the 121 orbits of norm -2 vectors from the (known) nann 0 vectors, and then apply it again to find the 665 orbits of nann -4 vectors from the vectors of nann 0 and -2. The neighbors of a strictly 24 dimensional odd unimodular lattice can be found as follows. If a norm -4 vector v E II . corresponds to the sum 25 1 of a strictly 24 dimensional odd unimodular lattice A and a !-dimensional lattice, then there are exactly two nonn-0 vectors of ll25,1 having inner product -2 with v, and these nann 0 vectors correspond to the two even neighbors of A. The enumeration of the odd 24-dimensional lattices. Figure 17.1 shows the neighborhood graph for the Niemeier lattices, which has a node for each Niemeier lattice. If A and B are neighboring Niemeier lattices, there are three integral lattices containing A n B, namely A, B, and an odd unimodular lattice C (cf. [Kne4]). An edge is drawn between nodes A and B in Fig. 17.1 for each strictly 24-dimensional unimodular lattice arising in this way. Thus there is a one-to-one correspondence between the strictly 24-dimensional odd unimodular lattices and the edges of our neighborhood graph. The 156 lattices are shown in Table 17 .I. Figure I 7. I also shows the corresponding graphs for dimensions 8 and 16.

Listing 1 - 4 of 4
Sort by