Resolvent (Galois theory)
= Resolvent
{disambiguate=Galois theory}
{wiki}
A <resolvent (Galois theory)> is an auxiliary <polynomial> built from expressions in the roots of a <polynomial>. The action of its <Galois group> on those expressions gives information about solvability and intermediate <field extensions>. A <Lagrange resolvent for a cubic> uses Fourier combinations of the three roots.