Author	Conway, J. H. author
Title	Sphere Packings, Lattices and Groups [electronic resource] / by J. H. Conway, N. J. A. Sloane
Imprint	New York, NY : Springer New York : Imprint: Springer, 1999
Edition	Third Edition
Connect to	http://dx.doi.org/10.1007/978-1-4757-6568-7
Descript	LXXIV, 706 p. online resource

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

1 Sphere Packings and Kissing Numbers -- 2 Coverings, Lattices and Quantizers -- 3 Codes, Designs and Groups -- 4 Certain Important Lattices and Their Properties -- 5 Sphere Packing and Error-Correcting Codes -- 6 Laminated Lattices -- 7 Further Connections Between Codes and Lattices -- 8 Algebraic Constructions for Lattices -- 9 Bounds for Codes and Sphere Packings -- 10 Three Lectures on Exceptional Groups -- 11 The Golay Codes and the Mathieu Groups -- 12 A Characterization of the Leech Lattice -- 13 Bounds on Kissing Numbers -- 14 Uniqueness of Certain Spherical Codes -- 15 On the Classification of Integral Quadratic Forms -- 16 Enumeration of Unimodular Lattices -- 17 The 24-Dimensional Odd Unimodular Lattices -- 18 Even Unimodular 24-Dimensional Lattices -- 19 Enumeration of Extremal Self-Dual Lattices -- 20 Finding the Closest Lattice Point -- 21 Voronoi Cells of Lattices and Quantization Errors -- 22 A Bound for the Covering Radius of the Leech Lattice -- 23 The Covering Radius of the Leech Lattice -- 24 Twenty-Three Constructions for the Leech Lattice -- 25 The Cellular Structure of the Leech Lattice -- 26 Lorentzian Forms for the Leech Lattice -- 27 The Automorphism Group of the 26-Dimensional Even Unimodular Lorentzian Lattice -- 28 Leech Roots and Vinberg Groups -- 29 The Monster Group and its 196884-Dimensional Space -- 30 A Monster Lie Algebra? -- Supplementary Bibliography

1. Mathematics
2. Chemometrics
3. Group theory
4. Applied mathematics
5. Engineering mathematics
6. Computational intelligence
7. Mathematics
8. Applications of Mathematics
9. Group Theory and Generalizations
10. Computational Intelligence
11. Math. Applications in Chemistry