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Dan Piponi

Oakland, CA

http://blog.sigfpe.com

Did a PhD in theta functions on Riemann surfaces many years ago. Up until recently I wrote software for movie effects, now I work for Google, and in my spare time play with applications of category theory to functional programming.
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Top Questions
Top Answers
298
Why is a topology made up of 'open' sets?
mathoverflow.net

231
Computer algebra errors
mathoverflow.net

218
Generate a random point within a circle (uniformly)
stackoverflow.com

163
Your favorite surprising connections in mathematics
mathoverflow.net

93
Papers that debunk common myths in the history of mathematics
mathoverflow.net

91
Relating category theory to programming language theory
mathoverflow.net

87
What is the exterior derivative intuitively?
mathoverflow.net

77
What's a groupoid? What's a good example of a groupoid?
mathoverflow.net

76
Short exact sequences every mathematician should know
mathoverflow.net

61
Cool problems to impress students with group theory
mathoverflow.net

55
Please explain the intuition behind the dual problem in optimization.
math.stackexchange.com

53
Abusing the algebra of algebraic data types - why does this work?
stackoverflow.com

48
Which mathematicians have influenced you the most?
mathoverflow.net

46
Why are $3D$ transformation matrices $4 \times 4$ instead of $3 \times 3$?
math.stackexchange.com

46
What are the most overloaded words in mathematics?
mathoverflow.net

45
Mathematics as a hobby
mathoverflow.net

42
Why are modular forms interesting?
mathoverflow.net

41
Rediscovery of lost mathematics
mathoverflow.net

41
Structures that turn out to exhibit a symmetry even though their definition doesn't
mathoverflow.net

40
What's your favorite equation, formula, identity or inequality?
mathoverflow.net

38
Affine transformation algorithm
stackoverflow.com

38
Mathematical applications of quantum field theory
mathoverflow.net

38
What are some interesting uses of higher-order functions?
stackoverflow.com

36
What are the most attractive Turing undecidable problems in mathematics?
mathoverflow.net

36
How can I input Greek symbols like \beta, \lambda in emacs?
stackoverflow.com

33
A book you would like to write
mathoverflow.net

31
What should be offered in undergraduate mathematics that's currently not (or isn't usually)?
mathoverflow.net

30
Is it faster to count down than it is to count up?
stackoverflow.com

27
Fields of mathematics that were dormant for a long time until someone revitalized them
mathoverflow.net

26
What math do I need to convert numbers according to this table?
stackoverflow.com

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