Stack Exchange

Henno Brandsma

the Netherlands

http://at.yorku.ca/cgi-bin/bbqa

Dutch topologist, now working in other fields.
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Top Questions
Top Answers
93
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
math.stackexchange.com

92
How secure is Chrome storing a password?
security.stackexchange.com

84
A map is continuous if and only if for every set, the image of closure is contained in the closure of image
math.stackexchange.com

71
Projection map being a closed map
math.stackexchange.com

67
Is $\mathbb R^3$ the square of some topological space?
mathoverflow.net

52
Prove $\limsup\limits_{n \to \infty} (a_n+b_n) \le \limsup\limits_{n \to \infty} a_n + \limsup\limits_{n \to \infty} b_n$
math.stackexchange.com

47
Show that the countable product of metric spaces is metrizable
math.stackexchange.com

44
Proof that product topology of subspace is same as induced product topology
math.stackexchange.com

33
Quick proofs of hard theorems
mathoverflow.net

29
Why do we need topological spaces?
math.stackexchange.com

27
Locally Constant Functions on Connected Spaces are Constant
math.stackexchange.com

26
What are the issues in modern set theory?
math.stackexchange.com

24
What is the reason for the term "zero dimensional" in the context of topology?
math.stackexchange.com

24
Perfect set without rationals
math.stackexchange.com

23
No. of possible dense subsets of a metric space
math.stackexchange.com

22
A quotient of a locally connected space is locally connected
math.stackexchange.com

22
Any open subset of $\Bbb R$ is a countable union of disjoint open intervals
math.stackexchange.com

22
A topology that is finer than a metrizable topology is also metrizable?
math.stackexchange.com

21
Make $2^8 + 2^{11} + 2^n$ a perfect square
math.stackexchange.com

21
Continuous image of a locally connected space which is not locally connected
math.stackexchange.com

21
Is every manifold a metric space?
math.stackexchange.com

20
What is your favorite proof of Tychonoff's Theorem?
mathoverflow.net

20
Are the rationals minus a point homeomorphic to the rationals?
math.stackexchange.com

19
Can Cantor set be the zero set of a continuous function?
mathoverflow.net

19
Topology vs Borel sigma-algebra on a set $X$
math.stackexchange.com

19
Why is the lower limit topology not metrizable?
math.stackexchange.com

19
Why don't we define neighbourhoods to be open sets?
math.stackexchange.com

18
Advantage of the more general notion of "neighborhoods" in topology
math.stackexchange.com

18
Is the intersection of two connected subspaces of a connected topological space is connected?
math.stackexchange.com

18
Are nets and filters useful in geometry and topology?
mathoverflow.net

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