Tag Archives: Gutenberg

Standing on the shoulders of Giants.

On Project Gutenberg, Math Books and Google Books and DJVU.

As many of you know Project Gutenberg is the brain child of Michael S. Hart.

The web site for Project Gutenberg is at


It collects in one place public domain works. The number of works of literature they have collected so far at Project Gutenberg is about 22,000. They use volunteers to proof read the converted works. The current process is a laborious one even with the use of very sophisticated technology.

A book is scanned and the imaged pages are feed into a computer OCR program usually ABBY Reader then a text file is produce and the page images and the text file are presented to volunteers in a process called distributed proof reading.

The Project Gutenberg mainly includes works in the English languages, only very few works on other languages are included. Another big disappointment with Project Gutenberg is that very few mathematical works are part of the project. This is not for lack of available material but I will guess for the difficulty in translating mathematical notations into \LaTeX or MathML.

Meanwhile some other options have appear that are trying to filled this vacuum. One other choice is the project initiated by Google. The project that I am referring to here is the Google Books. In this project Google has put a large collection of works this time including a big collection of mathematical books. The books from big university libraries are being scanned. Giving us back this treasures of old.

The works available for free on the net in Adobe PDF Reader format are the works of the greatest mathematicians in history. From the completed works of Gauss to Euler’s to Augustin L Cauchy,Evariste Galois, J Lagrange, Camille Jordan, Serre etc.

While the work done by Google is commendable they are still some issues. Some of the works have not being scanned properly and the pages are crooked and some of the pages the fonts are not readable. On the other hand it is great to be able to do a Google search on all the available classical books! There will be hopefully a day when we can just do research on existing material from the comfort of one’s own home.

Another similar effort is done by

the million book Project

similar in spirit to Google Books and to Project Gutenberg. Mainly all this projects are using the established Adobe PDF file format to publish the works. Unfortunately the file size for adobe PDF files is quite large since most of them are stored as images. For the average book the file size goes from 10 to 25 megabytes. This will be a problem for those with very slow connections to the internet to be able to access this great works!

On the other hand another technology similar to Adobe PDF have emerge. It’s produced by Lizardtech and name of the file format is DJVU (Pronounced “Deja Vu”!)

Their reader can be downloaded freely from


A big collection of mathematical works using the DJVU technology is freely accessible to those able to read Russian.

One is able to find a wonderful collection of math and physics Russian books at


there you can find books like

Р.Курант, Г.Роббинс. Что такое математика?

translation to the Russian of Courant and Robbins What is Mathematics? and many more jewels for free.

The majority of the books in the collection are oriented towards elementary mathematics.

You may encounter wonderful books by Yaglom, Perelman, Kolmogorov, Lovachevsky , Euclid even more modern books by Prasolov on Geometry and Topology and all that is needed is the DJVU reader a good internet connection and a bit of patience.

Below you will find a few samples of some classics available at Google Books.

Galois Completed Works at Google

Euler’s Differential Calculus

Agustin Louis Cauchy Cours D’Analyse

Joseph Louis Lagrange Traité de la résolution des équations numériques de tous les degrés.

Camille Jordan Traité des substitutions et des équations algébriques

and many more classics works by N. H. Abel, Jacobi, S. Lie, just to name a few more.

Another important source of mathematical classics is at

La bibliothèque numérique Gallica de la Bibliothèque Nationale de France .

Hope you will enjoy the free availability of very hight quality mathematical material!

This is a blog posting from www.isallaboutmath.com


Filed under google, internet, math, mathematics

Creating beautiful images

i1.gifvisited the Walter’s Museum in the nearby city of Baltimore Maryland. I was attracted to the museum by the Archimedes palimpsest. Unfortunately for me they did not even had a page on display of the famous Archimedes Palimpsest but taking advantage that I have done my trip there I decided to see the museum’s collection of illuminated Manuscripts.

All I can say is


Those monks really knew how to make something beautiful!

After Johannes Gutenberg invention, that is the movable types press, books became more ordinary items that many more people could afford and a big revolution happened when books became more accessible to people.

The down side to this is that books were no longer hand crafted but produce by machines and therefore not unique and not so beautiful! The quality of the images in books degraded very much.

Naturally there is exceptions to this.

Donald Knuth a mathematician and computer Scientist not happy with the way things had turned out for the second printing of his masterful treatise on Computer Algorithm “The Art of Computer Programming” decided to created two wonderful computer systems that are widely use today to produce once again not just beautiful Books but even better, beautiful Math books. Those programs are \TeX and METAFONT. \TeX is use for formatting pages and METAFONT was use by Knuth to create the Fonts to be use by \TeX.

Leslie Lamport another mathematician and computer scientist created a set of \TeX macros and the result was called \LaTeX. Similar transformation happened also to METAFONT. The original intention for METAFONT was to be use in the creation of beautiful Fonts that could be use by \TeX but sometime some programs are use in ways their original authors did not have in mind. Such is the case of METAFONT and METAPOST.

John D. Hobby transformed MetaFont into MetaPost.

How does METAFONT or for that matter METAPOST work?

METAPOST allows one to create Postscript files of beautiful figures. Using Postscript is important since is a language that most printers understand and using other programs one is able to easily translate postscript into other graphic formats.

Some times in the internet one is able to find small little treasures hidden in some hole.

While I was pondering on how to write this entry I was feeling tempted to start like

“In a hole in the ground there lived a hobbit. Not a nasty, dirty, wet hole, filled with the ends of worms and an oozy smell, nor yet dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort.”

This is the first beautiful paragraph of “The Hobbit” from Tolkien.

I wanted to begin that way because it almost seems like out of the hole in the ground I found John D. Hobby’s program in the web.

There is no need for anybody to own the program anymore!

Let the web do it for you!

Well here is the site to the METAPOST previewer on the web


This site was created by yet another Mathematician!:-)

Troy Henderson.

I have to say thank you Troy for placing this beauty on the net for all to use!

When you create a METAPOST images. You are creating a sort of computer assisted drawing. The same kind of drawing you do when you are using a computer program like the freely available Inkscape or Adobe’s Illustrator with mouse clicking and moving points but using METAPOST you communicate your intentions to the computer with words. Yes, you are writing in English or a subset of it, describing with this meta language what you like for MetaPost to do.

Henderson’s interface to METAPOST looks like this


Now let us do a small METAPOST program using Henderson’s Interface to MetaPost.

Draw an arbitrary triangle and the altitudes for this triangle.

By the end of this exercise we should end up with something that looks like this


The Metapost program for such an image will be like this

pair A,B,C,AA,BB,CC,H;
A=(0,0); B=(3cm,0); C=(1cm,2cm);
AA – A = whatever * (B-C) rotated 90;
AA = whatever [B,C];
BB – B = whatever * (A-C) rotated 90;
BB = whatever [A,C];
CC – C = whatever * (A-B) rotated 90;
CC = whatever [A,B];
H = whatever [A,AA];
H = whatever [B,BB];
draw A–AA withcolor red;
draw B–BB withcolor red;
draw C–CC withcolor red;
draw A–B–C–cycle withpen pencircle scaled 1bp withcolor blue;
draw H withpen pencircle scaled 2bp withcolor red;
label.lft(btex $A$ etex, A);
label.rt(btex $B$ etex, B);
label.urt(btex $C$ etex, C);


A program like this is not difficult to create, once you have master the rudiments of the METAPOST language. Let us explain line by line to see how we created the figure above.

The first line tells METAPOST of our intention to use 7 points A,B,C,H , AA,BB,CC.

A=(0,0); B=(3cm,0); C=(1cm,2cm);

In this line we have specified the Cartesian coordinates for point A,B and C. Now the tricky part is the following two lines

Here we are coercing METAPOST to do some Math for us.

AA – A = whatever * (B-C) rotated 90;
AA = whatever [B,C];

We are giving some mathematical intentions to Metapost. If we call AA the point at the feet of the altitudes then AA-A is the segment between AA and A. Notice the “whatever” is use to denote some factor we will let the computer figure out!

B-C is the segment between B and C and is rotated 90 degrees, now to tell Metapost that AA is somewhere in the segment BC we use the second line that is

AA = whatever [B,C];

and so on. The rest of the program is almost self explanatory but if you have wet your appetite and will like to do some magic with METAPOST I direct you to the Manual for more information about how to use the METAPOST program.

I hope you will enjoy the comfort of this Hobby hole as much as I did!

see John D Hobby A User’s Manual for METAPOST


see Troy Henderson A beginner’s guide to METAPOST for creating high-quality graphics .

you may also find very enjoyable this book about Metafont from the horse’s mouth. The Metafont Book.

follow this for Donald Knuth site at Stanford

for a collection of examples of Metapost programs and their output

go Metapost examples.

This is a blog posting from www.isallaboutmath.com

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Filed under geometry, graphics, math, mathematics