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Does Aut(F), the set of automorphisms of a field F, form a field under point-wise addition and multiplication of functions?

2007-01-06 11:14:55 · 2 answers · asked by Ed S 1 in Science & Mathematics Mathematics

2 answers

Aut(F) is clearly a group, under function composition. It is not a field, however.

If f is an Automorphism of F, then so is -f.
But f + (-f) = 0, while the zero map is certainly not an automorphism. Thus Aut(F) is not closed under addition, so cannot be a field, or even a ring when using pointwise addition as an operation.

2007-01-06 13:09:55 · answer #1 · answered by AnyMouse 3 · 0 0

I do not believe it forms a field (it does however form a group). I do not have a proof that it does not form a field, but I dont think so

2007-01-06 19:49:00 · answer #2 · answered by JasonM 7 · 0 0

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