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[parent] irreducible representations of the special linear group over $\mathbb{F}_p$ (Theorem)

Let $p\geq 5$ be a prime and let $G=\SL(2,\mathbb{F}_p)$ be the special linear group over the field with $p$ elements.

Lemma 1   The group $G=\SL(2,\F)$ has no non-trivial $1$ dimensional irreducible representations over $\F$ .
Proof. See an attached entry for the proof. $ \qedsymbol$

Next, we construct several irreducible representations for $G=\SL(2,\F)$ . For $0\leq m \leq p-1$ , let $V_m$ be the $\F$ vector space of homogeneous polynomials of degree $m$ in the independent variables $x$ and $y$ (of course, for $m=0$ , the representation is trivial). We give $V_m$ a structure of $\F[G]$ -module as follows. Let $p=p((x,y))\in V_m$ and $A\in \SL(2,\F)$ . We define: $$ A\cdot p := p( A\cdot (x,y)^t)=p(a_{11}x+a_{12}y,a_{21}x+a_{22}y)$$ where $t$ denotes transpose. The representations $V_m$ are, in a sense, all the irreducible representations of $G$ .

Theorem 1   For $0\leq m \leq p-1$ , the representations $V_m$ are irreducible representations of dimension $m+1$ over $\F$ . Furthermore, up to isomorphism, there are no other irreducible representations of $G$ over $\F$ .

Bibliography

1
Charles B. Thomas, Representations of Finite and Lie Groups, Imperial College Press, London.




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See Also: group representation, spin networks and spin foams


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$\mathit{SL}(2,\mathbb{F}_p)$ has no $1$ dimensional irreducible representations over $\mathbb{F}_p$ (Theorem) by alozano
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Cross-references: isomorphism, dimension, transpose, structure, variables, independent, degree, homogeneous polynomials, vector space, proof, representations, irreducible, group, field, special linear group, prime

This is version 2 of irreducible representations of the special linear group over $\mathbb{F}_p$, born on 2005-03-29, modified 2005-03-29.
Object id is 6914, canonical name is IrreducibleRepresentationsOfTheSpecialLinearGroupOverMathbbF_p.
Accessed 1724 times total.

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AMS MSC20G15 (Group theory and generalizations :: Linear algebraic groups :: Linear algebraic groups over arbitrary fields)

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