Dedekind's lemma in field theory says this:
Let E and L be fields, and σ1,…,σn:E⟶L be distinct field homomorphisms. Then σ1,…,σn are L-linearly independent, that is n∑i=1aiσi=0,ai∈L⟹(∀i)ai=0,
Is there an L-vector space in which this linear independence takes place? All field homomorphisms from E to L don't constitute a vector space because there is no neutral element in this set. Also, the sum of two homomorphisms may not be a homomorphism. If charL=2, and σ:E⟶L is a field homomorphism, then σ+σ=0 isn't a field homomorphism. I'm not really sure when the sum of two homomorphisms is again a homomorphism. Also, I'm not sure when the additive inverse of a homomorphism is again a homomorphism. Could you please help with these questions?
Answer
The space of all additive homomorphisms from E to L (E and L are considered as abelian groups w.r.t. addition). If f is such homomorphism and a∈L, then af maps x to a⋅f(x).
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