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Mathematics
Martin Brandenburg's user avatar
Martin Brandenburg's user avatar
Martin Brandenburg's user avatar
Martin Brandenburg
  • Member for 15 years, 3 months
  • Last seen more than a month ago
  • Berlin, Germany
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Top posts

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question
890
A proof of $\dim(R[T])=\dim(R)+1$ without prime ideals?
Apr 11, 2013
answer
183
Nice examples of groups which are not obviously groups
Apr 15, 2013
answer
173
If $AB = I$ then $BA = I$
Sep 2, 2010
question
127
Ring structure on the absolute Galois group of a finite field
Nov 17, 2013
answer
96
Order of a product of subgroups. Prove that $o(HK) = \frac{o(H)o(K)}{o(H \cap K)}$.
Jul 10, 2012
question
74
Geometric intuition for the tensor product of vector spaces
Sep 6, 2013
question
69
Is Stokes' Theorem natural in the sense of category theory?
Apr 8, 2015
answer
67
A non-noetherian ring with noetherian spectrum
Oct 21, 2010
answer
64
Submodule of free module over a p.i.d. is free even when the module is not finitely generated?
Jun 25, 2012
answer
63
Proving that $\mathbb{Z}[x]$ and $\mathbb{Q}[x]$ are not isomorphic.
May 5, 2013

Top Meta posts

9
19
30
When should an integral be considered a duplicate?
28
Should we fix titles that are making a wrong mathematical statement?
27
Surrendering to the duplicate flood
22
Recommendation when a duplicate cannot be found
18
Quality of inequalities questions for the mathematical olympics - spam activity (solved)

Top network posts

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305
Examples of common false beliefs in mathematics
119
A proof of $\dim(R[T])=\dim(R)+1$ without prime ideals?
96
$A$ is isomorphic to $A \oplus \mathbb{Z}^2$, but not to $A \oplus \mathbb{Z}$
88
When is $A$ isomorphic to $A^3$?
79
Rigidity of the category of schemes