Noether Equation on Artin and Milgram Galois Theory book












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On Section K Chapter 2 of Galois Book by Artin and Milgram it discusses Noether Equation, but I'm not sure what Noether Equation this is, I know about Noether Equation for symmetry in physics but not sure about one in relation to Galois Theory.



The book states that $x_sigma cdot sigma(x_tau ) = x_{sigma tau}$ satisfies Noether Equation where $sigma, tau$ are automorphisms of field $E$ and $x_sigma, x_tau in E$



If anyone knows what the Noether Equation they are referring to please elucidate :) Thanks in advance










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  • $begingroup$
    That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
    $endgroup$
    – Lord Shark the Unknown
    Jan 15 at 1:08










  • $begingroup$
    Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
    $endgroup$
    – reuns
    Jan 15 at 1:18


















0












$begingroup$


On Section K Chapter 2 of Galois Book by Artin and Milgram it discusses Noether Equation, but I'm not sure what Noether Equation this is, I know about Noether Equation for symmetry in physics but not sure about one in relation to Galois Theory.



The book states that $x_sigma cdot sigma(x_tau ) = x_{sigma tau}$ satisfies Noether Equation where $sigma, tau$ are automorphisms of field $E$ and $x_sigma, x_tau in E$



If anyone knows what the Noether Equation they are referring to please elucidate :) Thanks in advance










share|cite|improve this question









$endgroup$












  • $begingroup$
    That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
    $endgroup$
    – Lord Shark the Unknown
    Jan 15 at 1:08










  • $begingroup$
    Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
    $endgroup$
    – reuns
    Jan 15 at 1:18
















0












0








0





$begingroup$


On Section K Chapter 2 of Galois Book by Artin and Milgram it discusses Noether Equation, but I'm not sure what Noether Equation this is, I know about Noether Equation for symmetry in physics but not sure about one in relation to Galois Theory.



The book states that $x_sigma cdot sigma(x_tau ) = x_{sigma tau}$ satisfies Noether Equation where $sigma, tau$ are automorphisms of field $E$ and $x_sigma, x_tau in E$



If anyone knows what the Noether Equation they are referring to please elucidate :) Thanks in advance










share|cite|improve this question









$endgroup$




On Section K Chapter 2 of Galois Book by Artin and Milgram it discusses Noether Equation, but I'm not sure what Noether Equation this is, I know about Noether Equation for symmetry in physics but not sure about one in relation to Galois Theory.



The book states that $x_sigma cdot sigma(x_tau ) = x_{sigma tau}$ satisfies Noether Equation where $sigma, tau$ are automorphisms of field $E$ and $x_sigma, x_tau in E$



If anyone knows what the Noether Equation they are referring to please elucidate :) Thanks in advance







galois-theory noetherian






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share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 14 at 22:45









john takeuchijohn takeuchi

313




313












  • $begingroup$
    That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
    $endgroup$
    – Lord Shark the Unknown
    Jan 15 at 1:08










  • $begingroup$
    Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
    $endgroup$
    – reuns
    Jan 15 at 1:18




















  • $begingroup$
    That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
    $endgroup$
    – Lord Shark the Unknown
    Jan 15 at 1:08










  • $begingroup$
    Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
    $endgroup$
    – reuns
    Jan 15 at 1:18


















$begingroup$
That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
$endgroup$
– Lord Shark the Unknown
Jan 15 at 1:08




$begingroup$
That is the Noether equation they are talking about (it's a cocycle relation). Noether didn't just do one thing....
$endgroup$
– Lord Shark the Unknown
Jan 15 at 1:08












$begingroup$
Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
$endgroup$
– reuns
Jan 15 at 1:18






$begingroup$
Yes sorry this is a cocycle condition (Galois cohomology) that is a function $f : G to E^times$ such that $f(sigmatau )/f(sigma) = sigma (f(tau)/f(1))$ (which is a much weaker condition than $f(sigmatau )=sigma(f(tau ))$)
$endgroup$
– reuns
Jan 15 at 1:18












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