Computers and information

Here I comment on my intertwining with computers. (This page is seldom updated, sorry.)


Linux is an operating system (a free clone of Unix).   It was originally created by Linus Torvalds in 1991, and has been developed with the collective effort of many volonteers around the world.   I strongly adhere to this philosophy!
Frankly, I don't remember the last time I had a Windows operating system installed in my computer.  

TeX and LaTeX

TeX is an outstanding language, devised to produce high quality typesetting, including mathematical text.  I entered Donald Knuth's wonderlang in 1987 through the LaTeX door (writing my degree thesis using a popular wysiwig program had been an unfortunate experience).  Useful information about TeX can be retrieved from the TeX Users Group home page; see also the Comprehensive TeX Archive Network.

LaTeX is nowadays the standrd set of TeX macros. Since it is a bit tight, one of my first tasks was to give some flexibility to the "document styles", which years ago didn't possess elementary features such as chosing if you want your references to be called "Bibliography", or "Bibliografia"...   A later version of LaTeX has included most of this flexibility, mainly due to the Babel project.

I also wrote a file containing hyphenation patterns for Catalan.   Other people wrote similar files, and I don't know if they have been unified. In any case you can get it at the home page of the (not very much alive) Catalan TeX Users Group, Tirant lo TeX.

Another problem I worked on is the Catalan double ell ("ela geminada"), that appears in words like xarel·lo.   I wrote macros for producing a typographically pleasant middle dot; perhaps they should be slightly improved, but you can find them here (it is only 15 lines of TeX code).

I also wrote some macros to draw commutative diagrams, to deal with derivatives, to number equations in special ways, ..., and many more, but nowadays there are better solutions somewhere in the web.


Fortunately, those times when drawing graphics on a LaTeX document was painful passed away.   Nowadays TikZ allows you to write LaTeX-like code to produce beautiful graphics.   While trying to improve my TikZ, I found TikZ pour l'impatient particularly useful.
I have collected some of my usages of TikZ in this document.


Wikipedia has become one of my favourite sources of information (together with Google). I have written and edited several pages, mainly for the Catalan Wikipedia.   At a certain point, I was fed-up with the despotic behaviour of some administrators, so nowadays my collaboration is only occasional.


Maple is a program for performing symbolic mathematical computation, designed at the University of Waterloo some years ago. 
The mathematics courses at the Telecommunication School included from 1992 to 2009 laboratory sessions with Maple.  I was largely involved with them; I even dared to produce a booklet (1998) about Maple for the course on Vector Analysis.  Maple can also be useful to compute Lie brackets in 8-dimensional spaces...  More recently, I used Maple to study models for the vibration of rigid strings and their application to piano tuning.
Occasionally I have used other computation systems like Matlab, Mathematica, SageMath, Minitab...  The last one, R.


HTML (HyperText Markup Language) is the language used to compose pages for the World Wide Web (WWW) --as this one.   This language and the web as we know it were devised at the CERN in late 1990 --look at here.
I learned some HTML in order to create the home page of my research group in 1997.   Of course, writing raw HTML is not especially difficult if you know TeX previously.


PostScript is a page description language invented by Adobe some years ago.
Though PostScript is not intended for humans, learning something about it may be fun and interesting.   (Do you know what is reverse Polish notation?)   Years ago I devised some simple macros to draw circuits that were useful for some colleagues.   Nowadays this is useless!
You can find some information about PostScript at the home page of Ghostscript; you can also look at A First Guide to PostScript or these pages.


Perl, sometimes dubbed as pathologically eclectic rubbish lister, is a postmodern programming language, developed by Larry Wall.
I learned some about Perl, and the CGI library (created by L. Stein), to program some forms for the web page of the year 2000 session of the Fall Workshop on Geometry and Physics, as well as to publish its proceedings.
Some resources are and the Comprehensive Perl Archive Network.
Nowadays I wouldn't be able to program in Perl, nor in other languages that I learned far more time ago, like Fortran or Cobol. The notable exception could be Pascal.

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Last update: 22 May 2020