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Special Linear Group


The special linear group SL_n(R) over a commutative ring R with identity is the group of n×n matrices with entries in R and determinant 1. For a field F,

 SL_n(F)={A in GL_n(F):detA=1}.
(1)

It is the kernel of the determinant group homomorphism from the general linear group GL_n(F) to the multiplicative group F^× and is therefore a normal subgroup.

For the finite field F_q, where q is a prime power, writing |G| for the group order of a finite group G gives

 |SL_n(q)|=(|GL_n(q)|)/(q-1)=q^(n(n-1)/2)product_(j=2)^n(q^j-1).
(2)

The group center consists of the scalar matrices lambdaI for which lambda^n=1, where I is the n×n identity matrix. Its group order is gcd(n,q-1), and the resulting quotient group is the projective special linear group.

The group SL_n(R) is a real Lie group, while SL_n(C) is a complex Lie group. Their dimensions are n^2-1 over R and C, respectively, and their Lie algebra consists of the matrices having matrix trace zero,

 sl_n(F)={X in M_n(F):trX=0},
(3)

where M_n(F) denotes the set of all n×n matrices over F. The groups SL_n(R) and SL_n(C) are connected for n>=2, and SL_n(C) is simply connected. The finite examples SL_n(q) are Lie-type groups.


See also

Complex Lie Group, General Linear Group, Matrix Group, Projective Special Linear Group, Special Orthogonal Group, Special Unitary Group

Portions of this entry contributed by David Terr

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References

Conway, J. H.; Curtis, R. T.; Norton, S. P.; Parker, R. A.; and Wilson, R. A. "The Groups GL_n(q), SL_n(q), PGL_n(q), and PSL_n(q)=L_n(q)." §2.1 in Atlas of Finite Groups: Maximal Subgroups and Ordinary Characters for Simple Groups. Oxford, England: Clarendon Press, p. x, 1985.Grove, L. C. Classical Groups and Geometric Algebra. Providence, RI: American Mathematical Society, 2002.Hall, B. C. Lie Groups, Lie Algebras, and Representations: An Elementary Introduction, 2nd ed. Cham, Switzerland: Springer, 2015.

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Special Linear Group

Cite this as:

Weisstein, Eric W., with contributions by David Terr. "Special Linear Group." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/SpecialLinearGroup.html

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