Annali di Matematica Pura ed Applicata ( IF 1 ) Pub Date : 2020-08-24 , DOI: 10.1007/s10231-020-01025-x Eugenio Giannelli , Nguyen Ngoc Hung , A. A. Schaeffer Fry , Carolina Vallejo
We show that every finite group of order divisible by 2 or q, where q is a prime number, admits a \(\{2, q\}'\)-degree nontrivial irreducible character with values in \({\mathbb{Q}}(e^{2 \pi i /q})\). We further characterize when such character can be chosen with only rational values in solvable groups. These results follow from more general considerations on groups admitting a \(\{p, q\}'\)-degree nontrivial irreducible character with values in \({\mathbb{Q}}(e^{2 \pi i /p})\) or \({\mathbb{Q}}(e^{ 2 \pi i/q})\), for any pair of primes p and q. Along the way, we completely describe simple alternating groups admitting a \(\{p, q\}'\)-degree nontrivial irreducible character with rational values.
中文翻译:
$$ \ pi'$$π'-度和小环场的特征
我们表明,每个可被2或q整除的阶的有限组,其中q是质数,都接受一个\(\ {2,q \}'\)-级非平不可约字符,其值为\({\ mathbb {Q }}(e ^ {2 \ pi i / q})\)。我们进一步表征了何时只能以可解组的理性值来选择这种特征。这些结果来自对允许\(\ {p,q \}'\)度非平凡不可约字符的组具有\({\ mathbb {Q}}(e ^ {2 \ pi i / p })\)或\({\ mathbb {Q}}(e ^ {2 \ pi i / q})\),对于任意一对素数p和q。在此过程中,我们完整地描述了简单的交替组,它们允许具有合理值的\(\ {p,q \}'\)度非平凡不可约性。