Sage a beginning

I have made some rather basic calculus experiments in the online version of Sage, the open source mathematical system. It works really well, the Notebook interface is easy to use, and the mathematical typesetting is beautiful. I think a have found a new tool, as there is no need for a local installation, a browser is all that's needed. It is also a way to get introduced to Python programming.

What's in a good model

After reading Joshua M. Epstein comprehensive explanation of why we make models, I asked my self which elements does a good model contain? and well this is my list:

• Prose: because the use of a informal human language creates a mental image of the system.
• Illustration: because a drawing acts as a map of the system.
• Numbers: because numbers, originating from either measurements or assumptions, are inherent to system and they can be calculated up on.
• Algorithm: because to make even the simplest algorithm that describes a system the connections within the system has to be identified.
• Mathematics: because mathematical notation demands formality in thinking.
  

The spectrum of systems

I have read an article from New Scientist, about the financial system viewed as an ecological system. It made me think about heterogeneous versus homogeneous systems as the end points of a spectrum; where:

• Heterogeneous systems are robust but not optimal in an economic sense.
• Homogeneous systems are vulnerable but optimal in an economic sense.