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arXiv math/0009123math.AGmath.NT
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超椭圆Jacobian与射影线性伽罗瓦群

Hyperelliptic jacobians and projective linear Galois groups

Yuri G. Zarhin

摘要:

在他以前的论文(Math.Res.Letters 7(2000),123 - 132)中,作者证明了,在特征零处,超椭圆曲线$C: y^2=f(x)$的雅可比$J(C)$在基域$K$的代数闭包$K_a$上只有平凡的自同态,如果不可约多项式$f(x) \in K[x]$的伽罗瓦群$Gal(f)$是对称群$S_n$或交替群$A_n$。这里$n>4$是$f$的度数。在数学AG/0003002中,我们把这个结果推广到某些"较小"的伽罗瓦群的情况。特别地,我们处理了无穷级数$n=2^r+1, Gal(f)=L_2(2^r)$和$n=2^{4r+2}+1, Gal(f)=Sz(2^{2r+1})$。本文证明了$J(C)$在$K_a$上只有平凡自同态,如果$f$的根的集合可以与具有奇特征的有限域$F_q$上的$(m-1)$维射影空间$P^{m-1}(F_q)$相一致,使得作为其置换群的$Gal(f)$成为射影线性群$PGL(m,F_q)$或射影特殊线性群$L_m(q):=PSL(m,F_q)$.在这里,我们假设$m>2$。

英文摘要:

In his previous paper (Math. Res. Letters 7(2000), 123--132) the author proved that in characteristic zero the jacobian $J(C)$ of a hyperelliptic curve $C: y^2=f(x)$ has only trivial endomorphisms over an algebraic closure $K_a$ of the ground field $K$ if the Galois group $Gal(f)$ of the irreducible polynomial $f(x) \in K[x]$ is either the symmetric group $S_n$ or the alternating group $A_n$. Here $n>4$ is the degree of $f$. In math.AG/0003002 we extended this result to the case of certain ``smaller'' Galois groups. In particular, we treated the infinite series $n=2^r+1, Gal(f)=L_2(2^r)$ and $n=2^{4r+2}+1, Gal(f)=Sz(2^{2r+1})$. In the present paper we prove that $J(C)$ has only trivial endomorphisms over $K_a$ if the set of roots of $f$ could be identified with the $(m-1)$-dimensional projective space $P^{m-1}(F_q)$ over a finite field $F_q$ of odd characteristic in such a way that $Gal(f)$, viewed as its permutation group, becomes either the projective linear group $PGL(m,F_q)$ or the projective special linear group $L_m(q):=PSL(m,F_q)$. Here we assume that $m>2$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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