Rugby ball-shaped graph named after Joost van der Westhuizen

2017-02-21 14:26
Dr Johan Kok shows what the Joost graph looks like. (Seugnet van Zyl, Netwerk24)

Dr Johan Kok shows what the Joost graph looks like. (Seugnet van Zyl, Netwerk24)

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Pretoria – Not only has a poem been dedicated to the late Joost van der Westhuizen, but he has also had a mathematical graph named after him.

Dr Johan Kok, licensing chief at the Tshwane Metro Police in Pretoria, told Netwerk24 that a research project on tattooing graphs by him and Professor Naduvath Sudev of the Vidya Academy of Science and Technology in India, showed an interesting family of graphs.

Kok said, because of their shape, they immediately reminded him of rugby balls.

"After careful consideration – and with the permission of [Joost’s brother] Pieter van der Westhuizen as well as Joost – the family of graphs were named the J9 graphs. In that way, a specific graph forming part of the family of graphs, is called a Joost graph," he explained.

The research was published on March 1, 2016, on, a website run by Cornell University that enables experts in the fields of physics, maths and computer sciences to share their research internationally and to get access to other research papers before they are published.

Possible formal publication

"Tattooing is a newly-defined graph colouring approach that allows colours to mix as discrete objects within certain mathematical rules."

According to Kok, who has a PhD in maths, the colouring problem in graph theory has been researched for many years.

"In the research paper, we pointed out that the concept of tattooing has several applications, of which several still have to be explored and discovered."

He said their paper was submitted to a pre-eminent maths journal for possible formal publication.

Kok said mathematical research was what stimulated his mind.

He has submitted 70 mathematical research papers in the past five years or so.

"I could quite easily start working on a paper on Friday and submit it in draft form on the Monday."

Read more on:    joost van der westhuizen  |  pretoria  |  mathematics

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