词条 | Rudvalis group |
释义 |
In the area of modern algebra known as group theory, the Rudvalis group Ru is a sporadic simple group of order 214{{·}}33{{·}}53{{·}}7{{·}}13{{·}}29 = 145926144000 ≈ 1{{e|11}}. HistoryRu is one of the 26 sporadic groups and was found by {{Harvard citations |last=Rudvalis |first=Arunas |author-link=Arunas Rudvalis |year=1973 |year2=1984 |txt=yes}} and constructed by {{Harvard citations |last1 = Conway|first1 = John H.|author1-link = John H. Conway|last2 = Wales|first2 = David B.|year=1973 |txt=yes}}. Its Schur multiplier has order 2, and its outer automorphism group is trivial. In 1982 Robert Griess showed that Ru cannot be a subquotient of the monster group.[1] Thus it is one of the 6 sporadic groups called the pariahs. PropertiesThe Rudvalis group acts as a rank 3 permutation group on 4060 points, with one point stabilizer being the Ree group 2F4(2), the automorphism group of the Tits group. This representation implies a strongly regular graph srg(4060, 2304, 1328, 1208), i.e. each vertex has 2304 neighbors and 1755 non-neighbors, any two adjacent vertices have 1328 common neighbors, while any two non-adjacent ones have 1208 {{Harvard citations|last=Griess|year=1998|loc=p. 125}}. Its double cover acts on a 28-dimensional lattice over the Gaussian integers. The lattice has 4×4060 minimal vectors; if minimal vectors are identified whenever one is 1, i, –1, or –i times another, then the 4060 equivalence classes can be identified with the points of the rank 3 permutation representation. Reducing this lattice modulo the principal ideal gives an action of the Rudvalis group on a 28-dimensional vector space over the field with 2 elements. Duncan (2006) used the 28-dimensional lattice to construct a vertex operator algebra acted on by the double cover. {{harvtxt|Parrott|1976}} characterized the Rudvalis group by the centralizer of a central involution. {{harvtxt|Aschbacher|Smith|2004}} gave another characterization as part of their identification of the Rudvalis group as one of the quasithin groups.Maximal subgroups{{harvtxt|Wilson|1984}} found the 15 conjugacy classes of maximal subgroups of Ru as follows:
References1. ^Griess (1982)
|last1 = Conway |first1 = John H. |author1-link = John H. Conway |last2 = Wales |first2 = David B. |title = The construction of the Rudvalis simple group of order 145926144000 |journal = Journal of Algebra |issue = 3 |year = 1973 |pages = 538–548 |doi = 10.1016/0021-8693(73)90063-X |volume = 27 }}
|author = John F. Duncan |title = Moonshine for Rudvalis's sporadic group |year = 2008 |eprint = math/0609449v1 }}
|last = Griess |first = Robert L. |author-link = Robert Griess |title = The Friendly Giant |journal = Inventiones Mathematicae |issue = 1 |year = 1982 |pages = 1–102 |doi = 10.1007/BF01389186 |volume = 69 |bibcode = 1982InMat..69....1G }}
|last = Griess |first = Robert L. |title = Twelve Sporadic Groups |year = 1998 |publisher = Springer-Verlag }}
|last = Rudvalis |first = Arunas |author-link = Arunas Rudvalis |title = A new simple group of order 214 33 53 7 13 29 |journal = Notices of the American Mathematical Society |issue = 20 |year = 1973 |pages = A–95 }}
External links
1 : Sporadic groups |
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