k is a fieldLet $k$ be a field,L $L$, H is$H$ extension fields of k $k$, and $G=L\otimes_k H$,. I wonder why (I want to know the proof but I can't find) the prime ideal of G$G$ must be maximal ,and and its properties:
a) if L$L$ is spearableseparable over k$k$, then G$G$ is reduced.
b) if L$L$ is algebraic and purely inseparable over k $k$,then G then $G$ has a unique prime ideal.