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Mathematics
Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma
  • Member for 13 years, 7 months
  • Last seen more than 2 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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73
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2,066
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1,495
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591
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675
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Top posts
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108
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
Mar 3, 2011
102
A map is continuous if and only if for every set, the image of closure is contained in the closure of image
Feb 28, 2012
91
Projection map being a closed map
Feb 19, 2011
59
Prove $\limsup\limits_{n \to \infty} (a_n+b_n) \le \limsup\limits_{n \to \infty} a_n + \limsup\limits_{n \to \infty} b_n$
Jun 1, 2013
51
Proof that product topology of subspace is same as induced product topology
Nov 27, 2015
49
Show that the countable product of metric spaces is metrizable
Apr 15, 2013
36
Locally Constant Functions on Connected Spaces are Constant
Jun 12, 2011
30
Why do we need topological spaces?
Oct 6, 2020
28
What are the issues in modern set theory?
Mar 3, 2011
27
Perfect set without rationals
Dec 12, 2010
Top network posts
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92
How secure is Chrome storing a password?
72
Is $\mathbb R^3$ the square of some topological space?
67
Non-homeomorphic spaces that have continuous bijections between them
33
Quick proofs of hard theorems
23
What is your favorite proof of Tychonoff's Theorem?