- Steinberg representation
In
mathematics , the Steinberg representation, or Steinberg module, denoted by "St", is a particularlinear representation of agroup of Lie type over afinite field of characteristic "p", of degree equal to the largest power of "p" dividing the order of the group. These representations were discovered by harvs|txt=yes|authorlink=Robert Steinberg|first=Robert |last=Steinberg|year=1957.Most finite simple groups have exactly one Steinberg representation. A few have more than one because they are groups of Lie type in more than one way, and sporadic and most alternating groups have no Steinberg representation.
Properties
*The character value of "St" on an element "g" equals, up to sign, the order of a
Sylow subgroup of the centralizer of "g" if "g" has order prime to "p", and is zero if the order of "g" is divisible by "p".
*The Steinberg representation is equal to an alternating sum over allparabolic subgroup s containing aBorel subgroup , of the representation induced from the identity representation of the parabolic subgroup.
*The Steinberg representation is both regular and unipotent, and is the only irreducible regular unipotent representation (for the given prime "p").Applications
*The Steinberg representation is used in the proof of
Haboush's theorem (the Mumford conjecture).References
* "Finite Groups of Lie Type: Conjugacy Classes and Complex Characters" (Wiley Classics Library) by Roger W. Carter, John Wiley & Sons Inc; New Ed edition (August 1993) ISBN 0-471-94109-3
*springer|id=S/s130530|title= Steinberg module|first=Robert |last=Steinberg
*citation|first=R. |last=Steinberg|title=Prime power representations of finite linear groups II |journal=Canad. J. Math. |volume= 9 |year=1957|pages=347-351
*R. Steinberg, "Collected Papers" , Amer. Math. Soc. (1997) ISBN 0-8218-0576-2 pp. 580–586
*citation|first=J.E.|last= Humphreys|title=The Steinberg representation|journal= Bull. Amer. Math. Soc. (N.S.) |volume= 16 |year=1987|pages=237–263
url=http://www.ams.org/bull/1987-16-02/S0273-0979-1987-15512-1/home.html
id=MR|876960
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