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Viewing Version 7 of 'Lindemann-Weierstrass theorem'
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Title of object: Lindemann-Weierstrass theorem
Canonical Name: LindemannWeierstrassTheorem
Type: Theorem

Created on: 2004-04-21 18:33:11
Modified on: 2006-03-28 10:22:38

Creator: CWoo
Modifier: CWoo
Author: CWoo

Classification: msc:12D99, msc:11J85
Synonyms: Lindemann-Weierstrass theorem=Lindemann's theorem

Preamble:

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Content:

If $\alpha_1,\ldots,\alpha_n$ are linearly independent algebraic numbers over $\mathbb{Q}$, then $e^{\alpha_1},\ldots,e^{\alpha_n}$ are algebraically independent over $\mathbb{Q}$.

An equivalent version of the theorem \PMlinkescapetext{states} that if $\alpha_1,\ldots,\alpha_n$ are distinct algebraic numbers over $\mathbb{Q}$, then $e^{\alpha_1},\ldots,e^{\alpha_n}$ are linearly independent over $\mathbb{Q}$.

Some immediate consequences of this theorem:
\begin{itemize}
\item
If $\alpha$ is a non-zero algebraic number over $\mathbb{Q}$, then $e^{\alpha}$ is transcendental over $\mathbb{Q}$.
\item
$e$ is transcendental over $\mathbb{Q}$.
\item
$\pi$ is transcendental over $\mathbb{Q}$. As a result, it is impossible to ``square the circle''!
\end{itemize}

It is easy to see that $\pi$ is transcendental over $\mathbb{Q}(e)$ iff $e$ is transcendental over $\mathbb{Q}(\pi)$ iff $\pi$ and $e$ are algebraically independent. However, this is still an open question today.

Schanuel's conjecture is a generalization of the Lindemann-Weierstrass theorem. If Schanuel's conjecture were proven to be true, then the algebraic independence of $e$ and $\pi$ over $\mathbb{Q}$ can be shown.