Abstract
The 3-local geometry script g sign̄ = script g sign(Co1) of the sporadic simple group Co1 has been known to have a cover script g sign̂ = script g sign(224 · Co1) with a flag-transitive automorphism group which is a nonsplit extension of an elementary Abelian 2-group of rank 24 (the Leech lattice modulo 2) by Co1. It was conjectured that script g sign̂ was simply connected. We disprove this conjecture by constructing a double cover script g sign of script g sign̂. The automorphism group of script g sign is of the shape 21+24+ · Co1. However, it is not isomorphic to the involution centralizer of the Monster sporadic simple group.
Original language | English |
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Pages (from-to) | 237-244 |
Number of pages | 8 |
Journal | Geometriae Dedicata |
Volume | 73 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1998 |
Keywords
- Conway group
- Diagram geometries
- Sporadic groups
ASJC Scopus subject areas
- Geometry and Topology