Characteristic of a field is not equal to zero
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Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?
field-theory
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up vote
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Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?
field-theory
add a comment |
up vote
3
down vote
favorite
up vote
3
down vote
favorite
Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?
field-theory
Let $F$ be a field such that for every $x in F$ there exists a $k >0$ such that $x^k=1$. Does this imply that the characteristic of $F$ is strictly greater than zero?
field-theory
field-theory
asked 16 hours ago
J.Bosser
314210
314210
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Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.
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Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.
For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.
add a comment |
up vote
4
down vote
accepted
Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.
add a comment |
up vote
4
down vote
accepted
up vote
4
down vote
accepted
Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.
Yes. If the characteristic is zero then the prime subfield is isomorphic to $mathbb{Q}$, and this contains elements - e.g. 2 - whose nonzero powers are never equal to 1.
answered 16 hours ago
Matthew Towers
7,42922244
7,42922244
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Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.
For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.
add a comment |
up vote
3
down vote
Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.
For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.
add a comment |
up vote
3
down vote
up vote
3
down vote
Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.
For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.
Every field $F$ of characteristic $0$ contains (up to isomorphism) the field of rational numbers. If you take the rational number $frac{1}{2}$, say, then there is no integer $k>0$ such that $left(frac{1}{2}right)^k = 1$.
For a finite field with $q$ (prime power) elements, one has $x^{q-1}=1$ for each element $xne 0$ and $x^q=x$ for each element $x$.
edited 16 hours ago
answered 16 hours ago
Wuestenfux
3,0351410
3,0351410
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