Fixed field
= Fixed field
{wiki}
For a group $G$ of automorphisms of a field $L$, the fixed field is
$$
L^G=\{x\in L:g(x)=x\text{ for every }g\in G\}.
$$
For one automorphism $\sigma$, it is also written $L^\sigma$.
= Fixed field
{wiki}
For a group $G$ of automorphisms of a field $L$, the fixed field is
$$
L^G=\{x\in L:g(x)=x\text{ for every }g\in G\}.
$$
For one automorphism $\sigma$, it is also written $L^\sigma$.