250 reputation
19
bio website ptspts.blogspot.com
location Zurich, Switzerland
age 33
visits member for 3 years, 6 months
seen Jul 22 at 7:31

Programming for fun and profit. Hacking together TeX macros. Written gzip decompressor in PostScript. Writing multilingual programs, such as:

%:/*:if 0;"true" +s ||true<</;#|+q|*/include<stdio.h>/*\_/
{\if(%)}newpath/Times-Roman findfont 20 scalefont setfont(
%%)pop 72 72 moveto(Just another PostScript hacker,)show((
t)}. t:-write('Just another Prolog hacker,'),nl,halt. :-t.
:-initialization(t). end_of_file. %)pop pop showpage(-: */
int main(){return 0&printf("Just another C%s hacker,\n",1%
sizeof'2'*2+"++");}/*\fi}\csname @gobble\endcsname{\egroup
\let\LaTeX\TeX\ifx}\if00\documentclass{article}\begin{doc%
ument}\fi Just another \LaTeX\ hacker,\end{document}|if 0;
/(J.*)\$sh(.*)"/,print"$1Perl$2$/"if$_.=q # hack the lang!
/
sh=sh;test $BASH_VERSION &&sh=bash;test $POSIXLY_CORRECT&&
sh=sh;test  $ZSH_VERSION && sh=zsh;awk 'BEGIN{x="%c[A%c[K"
printf(x,27,27)}';echo "Just another $sh hacker," #)pop%*/

Mar
18
suggested suggested edit on Prove the convergence of $\lim_{n \rightarrow \infty} \frac{23^n}{n^{13}} \cdot \frac{1}{6}$
Oct
27
comment What is the simplest proof of the pythagorean theorem you know?
You also need to prove that in the figure on the right the large white area is a square. It's obvious that all its sides have the length $c$, but are the angles right angles?
Oct
2
revised Inequality…(RMO $1994$…question $8$)
moved the multiplication dot above the baseline
Oct
2
suggested suggested edit on Inequality…(RMO $1994$…question $8$)
Sep
27
awarded  Critic
Sep
26
comment Surprising identities / equations
There are not other integer solutions (except for $x=y$).
Sep
26
comment Surprising identities / equations
More explanation here: en.wikipedia.org/wiki/…
Sep
10
comment How can one prove that $e<\pi$?
Since $(1+1/n)^n<(1+1/n)^{n+1}$, it's enough to prove that the latter is decreasing. It starts from 4, then 3.375, then 3.16..., then 3.05..., then 2.98..., already smaller than 3.
May
14
awarded  Caucus
Apr
14
awarded  Nice Question
Apr
13
comment Who is the oldest? (in a non-revealing way)
@GregMartin: +1 for this answer. Thank you again for both of your answers, I've learned a lot from them. Also they gave me an opportunity to refine what I'm interested in.
Apr
13
revised Non-revealing maximum
added 182 characters in body
Apr
13
revised Who is the oldest? (in a non-revealing way)
added 355 characters in body
Apr
13
comment Who is the oldest? (in a non-revealing way)
Thank you for coming up with this answer and sharing it. I'm looking for an answer which doesn't need physical devices, but it can be implemented efficiently and cheaply by passing around notes written on (folded) paper. Also I'm looking for an answer which scales to 64-bit and then to 1024-bit ages. I've updated the question accordingly.
Apr
13
revised Who is the oldest? (in a non-revealing way)
added 185 characters in body
Apr
13
comment Who is the oldest? (in a non-revealing way)
It would be awesome if you could recast your solution to avoid the trusted third party and update your answer accordingly.
Apr
12
awarded  Yearling
Apr
12
comment Who is the oldest? (in a non-revealing way)
I don't think step 4 is OK. If two people compare their ages, and we repeat this many times to find the oldest person, some people get to know that they are older than specific other people. And that's too much information, because they are supposed to know only who the oldest is. Those people who are not the oldest must not gain any additional knowledge.
Apr
12
revised Who is the oldest? (in a non-revealing way)
added 165 characters in body
Apr
12
comment Who is the oldest? (in a non-revealing way)
Resolving ties is not too interesting to me. For simplicity we can assume for now that everybody has a unique age.