Lacking imagination, for understanding purposes I would like to see an example of an integral domain (with unity) that is not a field but has a quotient field of finite characteristic. If convenient an examples with finite and infinite quotient fields are appreciated.
A ring and a quotient field with finite characteristic
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abstract-algebra
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0@Peter: yup. The domains can be a little weirder, but are basically like that. One could have $\mathbb{F}_p[T^2,T^3]$ as a different example, or $\mathbb{F}_p[X,Y]$, but I think "polynomial ring" is a healthy idea of what sort of rings you are looking for. – 2011-06-29
2 Answers
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The ring of polynomials $\mathbb{F}_p[T]$ has a fraction field of $\mathbb{F}_p(T)$, which is of characteristic $p$. In fact, any $\mathbb{F}_p$-algebra that is an integral domain will have a fraction field of characteristic $p$.
There will not be any examples of non-field integral domains whose fraction field is a finite field, because this would imply that the original integral domain was finite, and any finite integral domain is already a field.
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Assuming you mean field of fractions...
There is no commutative domain which has a finite field of fractions and which is not itself a field: a theorem of Wedderburn asserts that a finite commutative domain is a field.
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0@Mark: Well, the theorem *implies* that, if you prefer :) – 2011-06-29