# Brendan McKay

### Brendan McKay is Professor in the Research School of Computer Science at The Australian National University

I am a theorist. I look at the fundamentals of mathematics in relation to networks

"I was always interested in science, and in school I wandered around physics and chemistry. But I kept coming back to my first love, mathematics."

Brendan received his PhD from Melbourne University in 1980. After three years at Vanderbilt University in the United States, he came to ANU in 1983. He has been Professor of Computer Science since 1998.

"I am a theorist. I look at the fundamentals of mathematics in relation to networks," says Brendan.

"A network is basically a collection of things with a relationship. All sorts of things can be a network - for example a set of cities is a network, and their relationship is the roads between them. Networks appear in every research area and walk of life, from psychology to engineering.

"My main focus is in 'random' networks; in other words, networks that 'just grow'. The Internet is a perfect example of a random network. Some parts have been planned, but in general it has developed through the independent and random decisions of many people.

"By developing a mathematical model of random networks we can use it to predict their future. In the case of the Internet, we can see how it might grow and thus what might be needed in future technology and infrastructure. We can also look at what might threaten it - how secure it is and how many nodes would need to be destroyed for it to be damaged."

Brendan is best known for his work on graph isomorphism - seeing whether two networks are really the same. The software he developed for this in the 1970s has been regarded as the leader in the field, and he is now updating it in collaboration with other researchers.

Brendan's work has a wide range of applications. "Since I am a theorist my work is generally used by others. But being theoretical does not mean that it is not practical," he says.

"In random networks, almost any field can use the theories and algorithms to see how a network develops - which can be used in the study of social processes or the spread of diseases. In graph isomorphism, my work has contributed to an amazing number and variety of other research projects, in particle physics, computer architecture, artificial intelligence, cryptology and many others. I am surprised and delighted when someone thinks of another application for my work."

Another area of study for Brendan is 'structure enumeration', finding all the possible networks that satisfy a particular rule. The most obvious application of this is in chemistry. Chemical molecules can be arranged in various ways, known as isomers. As molecules get larger, so do the number of ways the atoms can join up. Finding the potential atom 'networks' on a computer allows chemists to try to create new substances with new properties in the laboratory.

Brendan is 60 years old, however he has no plans to stop researching. "I have so many projects - seven or eight at any time. I expect I will go very slowly into retirement."

Brendan's other main interest is in debunking pseudoscience. In 2004 he received the Australian Skeptics Eureka Prize for Critical Thinking for his work in spreading the truth about the 'Bible codes'. "The fight against scientific ignorance in the community, and especially against those who foster it deliberately, is a worthwhile use of my professional talents."