2011
04.06
This week El Pais’ math challenge was easier to solve than previous ones (maybe that’s why I resolved it without using the computer this time 
).
The problem is the following: get a product magic square, that is, a 3×3 square whose product for numbers in every row, column or diagonal gives the same (unknown) amount . All numbers are unrepeated positive integers. It’s known that the number in the center cell is 15.
My approach was to assign each cell a variable name:
| $$a$$ |
$$b$$ |
$$c$$ |
| $$d$$ |
$$15$$ |
$$f$$ |
| $$g$$ |
$$h$$ |
$$i$$ |
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2011
03.26
This week’s math challenge of El País (Spanish video) is again about a graph. In this case, the graph is a cube (8 vertex, 12 edges) numbered as shown in the video.
An ant starts walking from vertex #1 and changes it direction at random on each vertex (might even turn back from the same edge it came from). Vertex #7 and #8 are poisoned. If the ant happens to walk into one of them it will die. The challenge consist in find out the probabilities of the ant dying or not and in which vertex (#7 or #8) when it does.
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2011
03.22
Yesterday at midnight was the deadline of El País math challenge which consisted in finding the Hamiltonian path of a given graph (or to give a demonstration it hadn’t any as it was the case). A friend of mine told me a simple and elegant demonstration based on graph coloration, which is the one explained in the video (the video is in Spanish but it’s my bet there are more demonstrations like this in English on the internet). If you can understand Spanish, I encourage you to watch the video. It’s really short, entertaining and easy to understand.
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2011
02.21
I have wanted to write about this for a long time. The fact is, as always, I’ve been overbusy with my projects, (e.g. with the ZX BASIC Compiler), that I haven’t had much free time.
I was born in the late 70′s. I grew up in the 80 which marked my adolescence (e.g. the ZX Spectrum, but also pop music and many other iconic things of that time). I consider myself a geek and I love new technologies. But, on one hand, I hate consumerism and being always on the cutting edge gadgets (especially if they are expensive). On the other one, if I had money and space I would create my own collection of microcomputers and other vintage machines (which could be consider another form of consumerism).
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2010
12.18
Bueno, tras un mes ajetreado, vuelvo a las andadas. En el post anterior dejé caer que no estaba seguro de mi decisión en el ámbito laboral (ya vi cosas que no me gustaron desde el primer día); no estaba muy convencido, pero como me he considerado siempre una persona insegura, pensé que se debía a eso. Sin embargo mi intuición no se equivocó. Evidentemente fue un error, del que afortunadamente salí bien parado, y de paso aprendí y vi las cosas más claras (hay momentos en la vida que te iluminan).
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