Solvability by Real Radicals and Fermat Primes

[摘要] We give a survey of old and new results concerning the expressibilityof the real roots of a solvable polynomial over a real number field byreal radicals. A characterization of Fermat primes is obtained interms of solvability by real radicals for certain ploynomials.

[学科分类] 数学（综合）

[关键词] congruence lattice;congruence-preserving extension