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Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma
  • Member for 16 years, 3 months
  • Last seen more than 3 years ago
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About

Henno Brandsma (1970-2022)

Got a PhD in topology in 98, now a cryptographer and security researcher.

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Top posts

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75
Is $\mathbb R^3$ the square of some topological space?
Apr 2, 2011
69
Non-homeomorphic spaces that have continuous bijections between them
Jul 5, 2010
34
Quick proofs of hard theorems
May 16, 2010
23
What is your favorite proof of Tychonoff's Theorem?
May 30, 2010
21
Locally compact Hausdorff space that is not normal
Feb 27, 2011
20
Can Cantor set be the zero set of a continuous function?
May 9, 2010
19
Are nets and filters useful in geometry and topology?
Jul 15, 2010
17
How many orders of infinity are there?
Jun 26, 2010
16
Discrete subspaces of Hausdorff spaces
Oct 16, 2010
15
What are interesting families of subsets of a given set?
Jan 31, 2010

Top network posts

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114
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
106
A map is continuous if and only if for every set, the image of closure is contained in the closure of image
95
How secure is Chrome storing a password?
94
Projection map being a closed map
63
Prove $\limsup\limits_{n \to \infty} (a_n+b_n) \le \limsup\limits_{n \to \infty} a_n + \limsup\limits_{n \to \infty} b_n$