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Mathematics
Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma's user avatar
Henno Brandsma
  • Member for 15 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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14,172
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6,533
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73
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2,150
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12
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2,077
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945
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11
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1,610
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593
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7
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1,102
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675
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866
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351
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Top posts

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114
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
Mar 3, 2011
106
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
94
Projection map being a closed map
Feb 19, 2011
63
Prove $\limsup\limits_{n \to \infty} (a_n+b_n) \le \limsup\limits_{n \to \infty} a_n + \limsup\limits_{n \to \infty} b_n$
Jun 1, 2013
59
Show that the countable product of metric spaces is metrizable
Apr 15, 2013
58
Proof that product topology of subspace is same as induced product topology
Nov 27, 2015
38
Locally Constant Functions on Connected Spaces are Constant
Jun 12, 2011
35
Closed Graph theorem with codomain compact Hausdorff
Oct 24, 2017
31
Why do we need topological spaces?
Oct 6, 2020
30
Show that every absolute retract space is contractible
Mar 6, 2022

Top network posts

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95
How secure is Chrome storing a password?
75
Is $\mathbb R^3$ the square of some topological space?
69
Non-homeomorphic spaces that have continuous bijections between them
34
Quick proofs of hard theorems
23
What is your favorite proof of Tychonoff's Theorem?