James Tauber's Blog 2004/10/14

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JotSpot

Most of the bloggers I read who were at WEB 2.0 have already blogged about JotSpot. I wasn't at WEB 2.0 but now it's my turn.

In short, I'm very excited about JotSpot which is a web development platform built on top of a wiki engine. As you may have guess already, I'm a big fan of wikis. I've also long been interested in placing real-time structured data in documents (it's one of the things that excited me about SGML in the first place).

I almost think of JotSpot as a team version of where I want to go with Leonardo. And whereas I'm focused largely on personal info hosting/publishing in Leonardo, JotSpot looks like it could be a great platform for building aggregators.

Beyond the information that's available at JotSpot you might want to check out Jon Udell's flash demo of JotSpot which made me feel like I was getting my own personal demo from JotSpot's co-founders.

I'd already been following Joe Kraus's blog, Bnoopy before JotSpot was announced. I hope he can find the time to get back to blogging more soon.

I just got in the beta program so I'll report more on JotSpot in the future.

by : Created on Oct. 14, 2004 : Last modified Feb. 8, 2005 : (permalink)

Poincare Project: Metric Spaces

A surface is more than just a set of points. Points on a surface have a notion of closeness that doesn't exist with a set unless we add some structure.

One way we can introduce the idea of closeness is to introduce the idea of the distance between points. That is, a function d that gives us a number for any pair of points.

To be a distance function, our function must meet some additional requirements:

• all distances must be non-negative: d(x,y)>=0
• the distance between x and y is zero if and only if x and y are the same point: d(x,y)=0 iff x=y
• the distance between x and y is the same as the distance between y and x. In other words, the distance function is always symmetric: d(x,y)=d(y,x)
• finally, the distance between two points can never exceed the sum of the distance between each of the points and a third point. This is often referred to as the triangle rule: d(x,z)<=d(x,y)+d(y,z)

A distance function is often called a metric. A set of points with a distance function is called a metric space.

A metric space clearly has a notion of closeness. A point y is closer to x than z is if d(y,x)<d(z,x).

UPDATE: next post

by : Created on Oct. 14, 2004 : Last modified Aug. 10, 2007 : (permalink)