imurme8
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A problem asks to find an abelian group V and a field F such that there exist two different actions, call them \cdot and \odot, of F on V such that V is an F-module.
A usual way to solve this is to take any vector space over a field with a non-trivial automorphism group, and define r\odot \mu to be f(r)\cdot \mu for f\in \text{Aut}(F), f\neq \iota.
My question is: is this essentially the only way? Given two different actions of F on V, can we construct a non-trivial automorphism of F?
Or, a weaker result: can we show that a prime field cannot act in two different ways on a module?
A usual way to solve this is to take any vector space over a field with a non-trivial automorphism group, and define r\odot \mu to be f(r)\cdot \mu for f\in \text{Aut}(F), f\neq \iota.
My question is: is this essentially the only way? Given two different actions of F on V, can we construct a non-trivial automorphism of F?
Or, a weaker result: can we show that a prime field cannot act in two different ways on a module?