

Graphs - jmillerinc
http://cdixon.org/2010/07/22/graphs/

======
dwine
I'm a computer scientist, and I call the (very old) study of graphs "graph
theory". How is "network theory" different?

And is it just me, or is it painful to read this? It has the feel of a student
taking an intro course on optimization, then exclaiming, "everything is an
optimization problem!" I mean, sure, this is true, but it's tautological and
feels forced to me.

And sorry, but Twitter's main innovation was discarding symmetry? People have
been subscribing (an asymmetric relation) to things on the internet and
otherwise for ages.

~~~
aamar
> Twitter's main innovation was discarding symmetry?

This is a common statement that benefits from explicit context: Twitter's
innovation specifically was importing the "asymmetric follow" into a social
network, a graph in which nodes represent individual people and in which
relations are generally public.

~~~
dwine
What was the social network with public relations between people that failed
because the "follow" was symmetric?

~~~
huangm
Symmetric follow doesn't have to fail for asymmetric follow to succeed.
Twitter's innovation allowed them to create and serve new use-cases. That's
all

------
ianbishop
>"One of Twitter’s central innovations was to discard symmetry: you can follow
someone without them following you."

Apparently Twitter rebranded the concept of a hyperlink.

>"I expect we’ll look back on the next few years as the golden age of graph
innovation."

I would say that the 'golden age of graph innovation' began much before this.
Which is why in Computer Science, as he describes, we have a special edition
of graph theory named 'network theory'. I wonder what that's for!

------
hooande
I've definitely noticed a trend towards graph based thinking in recent
computer science publications. My half baked theory on this is as follows:

Graph based thinking is a result of the rise of social networking. The term
"social network" wasn't common until I was a senior in college. Back then most
computer scientists thought of things in terms of matrices - rows and columns.
After 2004 when facebook became the most popular software in the college
universe, people became much more interested in graphs (social and otherwise).
I believe this lead many young computer scientists to start thinking in terms
of graphs - vertices and edges. If you read comp sci papers written by people
over the age of 30, many of them still express things in terms of matrices.

In my understanding, graphs can be faster to process and in many cases easier
to traverse. But I believe that the shift in thinking has more to do with
popular trends in software than it does any technical advantage of graphs over
other ways of thinking.

~~~
jey
No, your premise is wrong. Graphs are ancient within CS.

Linear algebra and graph theory do have some deep connections though.

------
albertsun
The idea of graphs is a very old and very interesting topic for mathematicians
too. See
[http://en.wikipedia.org/wiki/Seven_Bridges_of_K%C3%B6nigsber...](http://en.wikipedia.org/wiki/Seven_Bridges_of_K%C3%B6nigsberg)

