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
88
How secure is Chrome storing a password?
security.stackexchange.com

87
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
math.stackexchange.com

73
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

63
Projection map being a closed map
math.stackexchange.com

61
Is $\mathbb R^3$ the square of some topological space?
mathoverflow.net

49
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

38
Show that the countable product of metric spaces is metrizable
math.stackexchange.com

35
Proof that product topology of subspace is same as induced product topology
math.stackexchange.com

32
Quick proofs of hard theorems
mathoverflow.net

28
Why do we need topological spaces?
math.stackexchange.com

25
What are the issues in modern set theory?
math.stackexchange.com

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

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

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

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

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

21
Perfect set without rationals
math.stackexchange.com

20
What is the reason for the term “zero dimensional” in the context of topology?
math.stackexchange.com

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

19
Locally Constant Functions on Connected Spaces are Constant
math.stackexchange.com

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

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

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

18
What is your favorite proof of Tychonoff's Theorem?
mathoverflow.net

18
A quotient of a locally connected space is locally connected
math.stackexchange.com

17
Why is the lower limit topology not metrizable?
math.stackexchange.com

17
Why is PuTTYgen-created RSA public exponent(e) not in {3,17,65537}?
crypto.stackexchange.com

17
Is this statement true: a set is open if every point has a closed ball contained inside of the set
math.stackexchange.com

17
What's going on with “compact implies sequentially compact”?
math.stackexchange.com

17
How many orders of infinity are there?
mathoverflow.net

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