Attention conservation notice. The author reminisces about learning physics in high school, and claims that all too often, teaching was focused too much on concrete formulas, and not the unifying theory around them.
In elementary school, you may have learned D=RT (pronounced “dirt”), that is, distance is rate multiplied with time. This was mostly lies, but it was okay, because however tenuous the equation’s connection to the real world, teachers could use it to introduce the concept of algebraic manipulation, the idea that with just D=RT, you could also find out R if you knew D and T, and T if you knew D and R. Unless you were unusually bright, you didn’t know you were being lied to; you just learned to solve the word problems they’d give you.
Read more...
Update. The video of the talk can be found here: Galois Tech Talks on Vimeo: Categories are Databases.
On Thursday Dr. David Spivak presented Categories are Databases as a Galois tech talk. His slides are here, and are dramatically more accessible than the paper Simplicial databases. Here is a short attempt to introduce this idea to people who only have a passing knowledge of category theory.
An essential exercise when designing relational databases is the practice of object modeling using labeled graphs of objects and relationships. Visually, this involves drawing a bunch of boxes representing the objects being modeled, and then drawing arrows between the objects showing relationships they may have. We can then use this object model as the basis for a relational database schema.
Read more...
Git is very careful about your files: unless you tell it to be explicitly destructive, it will refuse to write over files that it doesn’t know about, instead giving an error like:
Untracked working tree file ‘foobar’ would be overwritten by merge.
In my work with Wizard, I frequently need to perform merges on working copies that have been, well, “less than well maintained”, e.g. they untarred a new version of the the source tree on the old directory and forgot to add the newly added files. When Wizard goes in and tries to automatically upgrade them to the new version the proper way, this results in all sorts of untracked working tree file complaints, and then we have to go and manually check on the untracked files and remove them once they’re fine.
Read more...