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huey's avatar

How do I Show that either f(1)=0 or f(1)=1 ii) Show that either f maps each element of F to 0 or f is injective.

Asked by huey (8points) March 2nd, 2010
6 responses
“Great Question” (1points)

Let f be a homomorphism from a field F onto an integral domain D…see extended details? i) Show that either f(1)=0 or f(1)=1 ii) Show that either f maps each element of F to 0 or f is injective.
This is for modern algebra. Do not understand it. Someone told me to use kernel, but we have not studied that yet so if someone could explain this without kernel, that would be great.

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squigish's avatar

fluther is not the place to answer homework questions. That said, I’m happy to help you. Check your private comments.

squigish's avatar

by the way, I’m a math PhD student, concentrating in abstract algebra.

ratboy's avatar

Hint: A field has exactly two ideals.

finkelitis's avatar

Remember that a homomorphism basically takes the ring structure with it (see the definition of a homomorphism, and compare to that last sentence). For part (i), maybe you could assume that 1 is not sent to 0 or 1, and see if you can find some kind of contradiction. Try playing with it a little.

Grisson's avatar

Ah… I see what you’re driving at. You are applying field theory to Sudoku! Clever!

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