Skip to main content
MathOverflow
Martin Brandenburg's user avatar
Martin Brandenburg's user avatar
Martin Brandenburg's user avatar
Martin Brandenburg
  • Member for 14 years, 11 months
  • Last seen this week
  • Berlin, Germany
Profile Activity
Stats
63,065
reputation
2.3m
reached
380
answers
352
questions
Communities
About

Badges
View all badges
11
gold badges
207
silver badges
424
bronze badges
Top tags
View all tags
948
Score
310
Posts
42
Posts %
754
Score
207
Posts
28
Posts %
650
Score
123
Posts
17
Posts %
215
Score
42
Posts
6
Posts %
163
Score
88
Posts
12
Posts %
143
Score
30
Posts
4
Posts %
Top posts
View all questions and answers
answer
296
Examples of common false beliefs in mathematics
May 5, 2010
question
111
A proof of $\dim(R[T])=\dim(R)+1$ without prime ideals?
Jun 21, 2014
question
94
$A$ is isomorphic to $A \oplus \mathbb{Z}^2$, but not to $A \oplus \mathbb{Z}$
Sep 12, 2015
question
87
When is $A$ isomorphic to $A^3$?
Dec 30, 2009
question
78
Rigidity of the category of schemes
Feb 28, 2011
question
74
$R$ is isomorphic to $R[X,Y]$, but not to $R[X]$
Dec 11, 2015
answer
73
What are the reasons for considering rings without identity?
Apr 26, 2010
question
71
Results from abstract algebra which look wrong (but are true)
Jan 19, 2023
answer
69
Example of an unnatural isomorphism
Aug 14, 2013
question
68
explicit big linearly independent sets
May 1, 2010
Top Meta posts
0
1
24
ChatGPT strikes MathOverflow
Top network posts
View all network posts
854
A proof of $\dim(R[T])=\dim(R)+1$ without prime ideals?
178
Nice examples of groups which are not obviously groups
167
If $AB = I$ then $BA = I$
121
Ring structure on the absolute Galois group of a finite field
91
Order of a product of subgroups. Prove that $o(HK) = \frac{o(H)o(K)}{o(H \cap K)}$.